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[
"Taxonomy",
"Phylogeny and APG system"
] | The 2009 revision of the [[Angiosperm Phylogeny Group]] system, [[APG III system|APG III]], places the order in the clade [[Monocotyledon|monocots]]. From the [[Dahlgren system]] of 1985 onwards, studies based mainly on morphology had identified the Asparagales as a distinct group, but had also included groups now located in Liliales, Pandanales and Zingiberales. Research in the 21st century has supported the [[monophyly]] of Asparagales, based on morphology, 18S rDNA, and other DNA sequences, although some phylogenetic reconstructions based on molecular data have suggested that Asparagales may be paraphyletic, with Orchidaceae separated from the rest. Within the monocots, Asparagales is the [[sister group]] of the [[commelinid]] clade. This [[cladogram]] shows the placement of Asparagales within the orders of [[Lilianae]] ''[[sensu]]'' Chase & Reveal (monocots) based on molecular phylogenetic evidence. The [[lilioid monocot]] orders are bracketed, namely [[Petrosaviales]], [[Dioscoreales]], [[Pandanales]], [[Liliales]] and Asparagales. These constitute a [[Paraphyly|paraphyletic]] assemblage, that is groups with a common ancestor that do not include all direct descendants (in this case commelinids as the sister group to Asparagales); to form a clade, all the groups joined by thick lines would need to be included. While Acorales and Alismatales have been collectively referred to as "[[alismatid monocots]]" (basal or early branching monocots), the remaining clades (lilioid and [[commelinid]] monocots) have been referred to as the "core monocots". The relationship between the orders (with the exception of the two sister orders) is [[wikt:pectinate|pectinate]], that is diverging in succession from the line that leads to the commelinids. Numbers indicate [[crown group]] (most recent common ancestor of the sampled species of the clade of interest) divergence times in [[mya (unit)|mya]] (million years ago). | 786 | Asparagales | [
"Asparagales",
"Angiosperm orders",
"Extant Late Cretaceous first appearances"
] | [
"Taxonomy of Liliaceae"
] |
[
"Taxonomy",
"Subdivision"
] | A [[phylogenetic tree]] for the Asparagales, generally to family level, but including groups which were recently and widely treated as families but which are now reduced to subfamily rank, is shown below. The tree shown above can be divided into a basal paraphyletic group, the 'lower Asparagales (asparagoids)', from Orchidaceae to Asphodelaceae, and a well-supported monophyletic group of 'core Asparagales' (higher asparagoids), comprising the two largest families, Amaryllidaceae ''sensu lato'' and Asparagaceae ''sensu lato''. Two differences between these two groups (although with exceptions) are: the mode of [[microsporogenesis]] and the position of the ovary. The 'lower Asparagales' typically have simultaneous microsporogenesis (i.e. cell walls develop only after both [[meiosis|meiotic]] divisions), which appears to be an [[apomorphy]] within the monocots, whereas the 'core Asparagales' have reverted to successive microsporogenesis (i.e. cell walls develop after each division). The 'lower Asparagales' typically have an [[inferior ovary]], whereas the 'core Asparagales' have reverted to a [[superior ovary]]. A 2002 morphological study by Rudall treated possessing an inferior ovary as a [[synapomorphy]] of the Asparagales, stating that reversions to a superior ovary in the 'core Asparagales' could be associated with the presence of nectaries below the ovaries. However, Stevens notes that superior ovaries are distributed among the 'lower Asparagales' in such a way that it is not clear where to place the evolution of different ovary morphologies. The position of the ovary seems a much more flexible character (here and in other [[angiosperm]]) than previously thought. | 786 | Asparagales | [
"Asparagales",
"Angiosperm orders",
"Extant Late Cretaceous first appearances"
] | [
"Taxonomy of Liliaceae"
] |
[
"Taxonomy",
"Subdivision",
"Changes to family structure in APG III"
] | The [[APG III system]] when it was published in 2009, greatly expanded the families [[Xanthorrhoeaceae]], [[Amaryllidaceae]], and [[Asparagaceae]]. Thirteen of the families of the earlier [[APG II system]] were thereby reduced to subfamilies within these three families. The expanded Xanthorrhoeaceae is now called "Asphodelaceae". The APG II families (left) and their equivalent APG III subfamilies (right) are as follows: | 786 | Asparagales | [
"Asparagales",
"Angiosperm orders",
"Extant Late Cretaceous first appearances"
] | [
"Taxonomy of Liliaceae"
] |
[
"Taxonomy",
"Subdivision",
"Structure of Asparagales",
"Orchid clade"
] | [[Orchidaceae]] is the largest family of all [[angiosperm]] and hence by far the largest in the order. The [[Dahlgren system]] recognized three families of orchids, but DNA sequence analysis later showed that these families are [[polyphyletic]] and so should be combined. Several studies suggest (with high bootstrap support) that Orchidaceae is the sister of the rest of the Asparagales. Other studies have placed the orchids differently in the phylogenetic tree, generally among the [[Boryaceae]]-[[Hypoxidaceae]] clade. The position of Orchidaceae shown above seems the best current hypothesis, but cannot be taken as confirmed. Orchids have simultaneous microsporogenesis and inferior ovaries, two characters that are typical of the 'lower Asparagales'. However, their nectaries are rarely in the septa of the ovaries, and most orchids have dust-like seeds, atypical of the rest of the order. (Some members of [[Vanilloideae]] and [[Cypripedioideae]] have crustose seeds, probably associated with dispersal by birds and mammals that are attracted by fermenting fleshy fruit releasing fragrant compounds, e.g. [[vanilla]].) In terms of the number of species, Orchidaceae diversification is remarkable. However, although the other Asparagales may be less rich in species, they are more variable morphologically, including tree-like forms. | 786 | Asparagales | [
"Asparagales",
"Angiosperm orders",
"Extant Late Cretaceous first appearances"
] | [
"Taxonomy of Liliaceae"
] |
[
"Taxonomy",
"Subdivision",
"Structure of Asparagales",
"Boryaceae to Hypoxidaceae"
] | The four families excluding [[Boryaceae]] form a well-supported clade in studies based on DNA sequence analysis. All four contain relatively few species, and it has been suggested that they be combined into one family under the name Hypoxidaceae ''sensu lato''. The relationship between Boryaceae (which includes only two genera, ''[[Borya]]'' and ''[[Alania (plant)|Alania]]''), and other Asparagales has remained unclear for a long time. The Boryaceae are [[mycorrhiza]], but not in the same way as orchids. Morphological studies have suggested a close relationship between Boryaceae and Blandfordiaceae. There is relatively low support for the position of Boryaceae in the tree shown above. | 786 | Asparagales | [
"Asparagales",
"Angiosperm orders",
"Extant Late Cretaceous first appearances"
] | [
"Taxonomy of Liliaceae"
] |
[
"Taxonomy",
"Subdivision",
"Structure of Asparagales",
"Ixioliriaceae to Xeronemataceae"
] | The relationship shown between [[Ixioliriaceae]] and [[Tecophilaeaceae]] is still unclear. Some studies have supported a clade of these two families, others have not. The position of [[Doryanthaceae]] has also varied, with support for the position shown above, but also support for other positions. The clade from [[Iridaceae]] upwards appears to have stronger support. All have some genetic characteristics in common, having lost Arabidopsis-type [[telomere]]. Iridaceae is distinctive among the Asparagales in the unique structure of the [[inflorescence]] (a rhipidium), the combination of an inferior ovary and three stamens, and the common occurrence of unifacial leaves whereas bifacial leaves are the norm in other Asparagales. Members of the clade from [[Iridaceae]] upwards have infra-locular septal nectaries, which Rudall interpreted as a driver towards secondarily superior ovaries. | 786 | Asparagales | [
"Asparagales",
"Angiosperm orders",
"Extant Late Cretaceous first appearances"
] | [
"Taxonomy of Liliaceae"
] |
[
"Taxonomy",
"Subdivision",
"Structure of Asparagales",
"Asphodelaceae + 'core Asparagales'"
] | The next node in the tree (Xanthorrhoeaceae ''sensu lato'' + the 'core Asparagales') has strong support. 'Anomalous' secondary thickening occurs among this clade, e.g. in ''[[Xanthorrhoea]]'' (family Asphodelaceae) and ''[[Dracaena (plant)|Dracaena]]'' (family Asparagaceae ''sensu lato''), with species reaching tree-like proportions. The 'core Asparagales', comprising Amaryllidaceae ''sensu lato'' and Asparagaceae ''sensu lato'', are a strongly supported clade, as are clades for each of the families. Relationships within these broadly defined families appear less clear, particularly within the Asparagaceae ''sensu lato''. Stevens notes that most of its subfamilies are difficult to recognize, and that significantly different divisions have been used in the past, so that the use of a broadly defined family to refer to the entire clade is justified. Thus the relationships among subfamilies shown above, based on [[APWeb]] , is somewhat uncertain. | 786 | Asparagales | [
"Asparagales",
"Angiosperm orders",
"Extant Late Cretaceous first appearances"
] | [
"Taxonomy of Liliaceae"
] |
[
"Taxonomy",
"Evolution"
] | Several studies have attempted to date the evolution of the Asparagales, based on phylogenetic evidence. Earlier studies generally give younger dates than more recent studies, which have been preferred in the table below. A 2009 study suggests that the Asparagales have the highest diversification rate in the monocots, about the same as the order [[Poales]], although in both orders the rate is little over half that of the [[eudicot]] order [[Lamiales]], the clade with the highest rate. | 786 | Asparagales | [
"Asparagales",
"Angiosperm orders",
"Extant Late Cretaceous first appearances"
] | [
"Taxonomy of Liliaceae"
] |
[
"Taxonomy",
"Comparison of family structures"
] | The taxonomic diversity of the monocotyledons is described in detail by Kubitzki. Up-to-date information on the Asparagales can be found on the [[Angiosperm Phylogeny Website]]. The APG III system's family circumscriptions are being used as the basis of the Kew-hosted ''World Checklist of Selected Plant Families''. With this circumscription, the order consists of 14 families (Dahlgren had 31) with approximately 1120 genera and 26000 species. Order Asparagales (-) Family [[Amaryllidaceae]] (including Agapanthaceae , Alliaceae ) (-) Family [[Asparagaceae]] (including Agavaceae <nowiki>[which includes Anemarrhenaceae, Anthericaceae, Behniaceae and Herreriaceae]</nowiki>, Aphyllanthaceae , Hesperocallidaceae , Hyacinthaceae , Laxmanniaceae , Ruscaceae <nowiki>[which includes Convallariaceae]</nowiki> and Themidaceae ) (-) Family [[Asteliaceae]] (-) Family [[Blandfordiaceae]] (-) Family [[Boryaceae]] (-) Family [[Doryanthaceae]] (-) Family [[Hypoxidaceae]] (-) Family [[Iridaceae]] (-) Family [[Ixioliriaceae]] (-) Family [[Lanariaceae]] (-) Family [[Orchidaceae]] (-) Family [[Tecophilaeaceae]] (-) Family Xanthorrhoeaceae (including Asphodelaceae and Hemerocallidaceae ), now [[Asphodelaceae]] (-) Family [[Xeronemataceae]] The earlier 2003 version, [[APG II system|APG II]], allowed 'bracketed' families, i.e. families which could either be segregated from more comprehensive families or could be included in them. These are the families given under "including" in the list above. APG III does not allow bracketed families, requiring the use of the more comprehensive family; otherwise the circumscription of the Asparagales is unchanged. A separate paper accompanying the publication of the 2009 APG III system provided subfamilies to accommodate the families which were discontinued. The first APG system of [[APG system|1998]] contained some extra families, included in square brackets in the list above. Two older systems which use the order Asparagales are the [[Dahlgren system]] and the [[Kubitzki system]]. The families included in the circumscriptions of the order in these two systems are shown in the first and second columns of the table below. The equivalent family in the modern APG III system (see below) is shown in the third column. Note that although these systems may use the same name for a family, the genera which it includes may be different, so the equivalence between systems is only approximate in some cases. | 786 | Asparagales | [
"Asparagales",
"Angiosperm orders",
"Extant Late Cretaceous first appearances"
] | [
"Taxonomy of Liliaceae"
] |
[
"Uses"
] | The Asparagales include many important [[crop plants]] and [[ornamental plants]]. Crops include [[Allium]], [[Asparagus]] and [[Vanilla (genus)|Vanilla]], while ornamentals include [[iris (plant)|irises]], [[hyacinths]] and [[orchids]]. | 786 | Asparagales | [
"Asparagales",
"Angiosperm orders",
"Extant Late Cretaceous first appearances"
] | [
"Taxonomy of Liliaceae"
] |
[] | The '''Alismatales''' ('''alismatids''') are an order of [[flowering plant]] including about 4500 species. Plants assigned to this order are mostly tropical or aquatic. Some grow in fresh water, some in marine habitats. | 787 | Alismatales | [
"Alismatales",
"Angiosperm orders"
] | [] |
[
"Description"
] | The Alismatales comprise [[herbaceous]] flowering plants of often aquatic and marshy habitats, and the only monocots known to have green [[embryo]] other than the [[Amaryllidaceae]]. They also include the only marine angiosperms growing completely submerged, the [[seagrass]]. The [[flower]] are usually arranged in [[inflorescence]], and the mature seeds lack [[endosperm]]. Both marine and freshwater forms include those with staminate flowers that detach from the parent plant and float to the surface. There they can pollinate carpellate flowers floating on the surface via long pedicels. In others, pollination occurs underwater, where pollen may form elongated strands, increasing chance of success. Most aquatic species have a totally submerged juvenile phase, and flowers are either floating or emergent. Vegetation may be totally submersed, have floating leaves, or protrude from the water. Collectively, they are commonly known as "water plantain". | 787 | Alismatales | [
"Alismatales",
"Angiosperm orders"
] | [] |
[
"Taxonomy"
] | The Alismatales contain about 165 genera in 13 families, with a [[cosmopolitan distribution]]. [[Phylogenetically]], they are [[basal monocot]], diverging early in evolution relative to the [[lilioid]] and [[commelinid]] [[monocot]] lineages. Together with the [[Acorales]], the Alismatales are referred to informally as the alismatid monocots. | 787 | Alismatales | [
"Alismatales",
"Angiosperm orders"
] | [] |
[
"Taxonomy",
"Early systems"
] | The [[Cronquist system]] (1981) places the Alismatales in subclass [[Alismatidae]], class [[Liliopsida]] [= monocotyledons] and includes only three families as shown: (-) [[Alismataceae]] (-) [[Butomaceae]] (-) [[Limnocharitaceae]] Cronquist's subclass Alismatidae conformed fairly closely to the order Alismatales as defined by APG, minus the Araceae. The [[Dahlgren system]] places the Alismatales in the superorder [[Alismatanae]] in the subclass [[Liliidae]] [= monocotyledons] in the class [[Magnoliopsida]] [= angiosperms] with the following families included: (-) [[Alismataceae]] (-) [[Aponogetonaceae]] (-) [[Butomaceae]] (-) [[Hydrocharitaceae]] (-) [[Limnocharitaceae]] In Tahktajan's classification (1997), the order Alismatales contains only the Alismataceae and Limnocharitaceae, making it equivalent to the Alismataceae as revised in APG-III. Other families included in the Alismatates as currently defined are here distributed among 10 additional orders, all of which are assigned, with the following exception, to the Subclass Alismatidae. Araceae in Tahktajan 1997 is assigned to the [[Arales]] and placed in the Subclass Aridae; Tofieldiaceae to the [[Melanthiales]] and placed in the [[Liliidae]]. | 787 | Alismatales | [
"Alismatales",
"Angiosperm orders"
] | [] |
[
"Taxonomy",
"Angiosperm Phylogeny Group"
] | The Angiosperm Phylogeny Group system ([[APG system|APG]]) of 1998 and [[APG II system|APG II]] (2003) assigned the Alismatales to the monocots, which may be thought of as an unranked clade containing the families listed below. The biggest departure from [[list of systems of plant taxonomy|earlier systems]] (see below) is the inclusion of family Araceae. By its inclusion, the order has grown enormously in number of species. The family Araceae alone accounts for about a hundred genera, totaling over two thousand species. The rest of the families together contain only about five hundred species, many of which are in very small families. The [[APG III system]] (2009) differs only in that the [[Limnocharitaceae]] are combined with the Alismataceae; it was also suggested that the genus ''[[Maundia]]'' (of the [[Juncaginaceae]]) could be separated into a monogeneric family, the [[Maundiaceae]], but the authors noted that more study was necessary before the Maundiaceae could be recognized. (-) order Alismatales ''[[sensu]]'' APG III (-) family [[Alismataceae]] (''including'' [[Limnocharitaceae]]) (-) family [[Aponogetonaceae]] (-) family [[Araceae]] (-) family [[Butomus|Butomaceae]] (-) family [[Cymodoceaceae]] (-) family [[Hydrocharitaceae]] (-) family [[Juncaginaceae]] (-) family [[Posidoniaceae]] (-) family [[Potamogetonaceae]] (-) family [[Ruppiaceae]] (-) family [[Scheuchzeriaceae]] (-) family [[Tofieldiaceae]] (-) family [[Zosteraceae]] In [[APG IV]] (2016), it was decided that evidence was sufficient to elevate ''[[Maundia]]'' to family level as the [[monogeneric]] Maundiaceae. The authors considered including a number of the smaller orders within the Juncaginaceae, but an online survey of botanists and other users found little support for this "[[lumping]]" approach. Consequently, the family structure for APG IV is: (-) family [[Alismataceae]] (''including'' [[Limnocharitaceae]]) (-) family [[Aponogetonaceae]] (-) family [[Araceae]] (-) family [[Butomus|Butomaceae]] (-) family [[Cymodoceaceae]] (-) family [[Hydrocharitaceae]] (-) family [[Juncaginaceae]] (-) family [[Maundiaceae]] (-) family [[Posidoniaceae]] (-) family [[Potamogetonaceae]] (-) family [[Ruppiaceae]] (-) family [[Scheuchzeriaceae]] (-) family [[Tofieldiaceae]] (-) family [[Zosteraceae]] | 787 | Alismatales | [
"Alismatales",
"Angiosperm orders"
] | [] |
[
"Taxonomy",
"Phylogeny"
] | [[Cladogram]] showing the orders of monocots ([[Lilianae]] ''[[sensu]]'' Chase & Reveal) based on molecular phylogenetic evidence: | 787 | Alismatales | [
"Alismatales",
"Angiosperm orders"
] | [] |
[] | The '''Apiales''' are an [[Order (biology)|order]] of [[flowering plant]]. The [[Family (biology)|families]] are those recognized in the [[APG III system]]. This is typical of the newer [[Biological classification|classifications]], though there is some slight variation and in particular, the Torriceliaceae may be divided. Under this definition, well-known members include [[carrot]], [[celery]], [[parsley]], and ''[[Hedera helix]]'' (English ivy). The order Apiales is placed within the [[asterid]] group of [[eudicots]] as circumscribed by the APG III system. Within the asterids, Apiales belongs to an [[Taxonomic rank|unranked]] group called the [[campanulids]], and within the campanulids, it belongs to a [[clade]] known in [[phylogenetic nomenclature]] as [[Apiidae]]. In 2010, a [[subclade]] of Apiidae named [[Dipsapiidae]] was defined to consist of the three orders: Apiales, [[Paracryphiales]], and [[Dipsacales]]. | 788 | Apiales | [
"Apiales",
"Angiosperm orders",
"Taxa named by Takenoshin Nakai"
] | [] |
[
"Taxonomy"
] | Under the [[Cronquist system]], only the Apiaceae and Araliaceae were included here, and the restricted order was placed among the rosids rather than the asterids. The [[Pittosporaceae]] were placed within the [[Rosales]], and many of the other forms within the family [[Cornaceae]]. ''[[Pennantia]]'' was in the family [[Icacinaceae]]. In the classification system of [[Rolf Dahlgren|Dahlgren]] the families Apiaceae and Araliaceae were placed in the order Ariales, in the [[superorder]] Araliiflorae (also called Aralianae). The present understanding of the Apiales is fairly recent and is based upon comparison of [[DNA sequences]] by [[Phylogenetics|phylogenetic]] methods. The [[Circumscription (taxonomy)|circumscriptions]] of some of the families have changed. In 2009, one of the subfamilies of Araliaceae was shown to be [[polyphyletic]]. | 788 | Apiales | [
"Apiales",
"Angiosperm orders",
"Taxa named by Takenoshin Nakai"
] | [] |
[
"Gynoecia"
] | The largest and obviously closely related families of Apiales are [[Araliaceae]], [[Myodocarpaceae]] and [[Apiaceae]], which resemble each other in the structure of their [[gynoecium|gynoecia]]. In this respect however, the [[Pittosporaceae]] is notably distinct from them. Typical syncarpous gynoecia exhibit four vertical zones, determined by the extent of fusion of the carpels. In most plants the synascidiate (i.e. "united bottle-shaped") and symplicate zones are fertile and bear the ovules. Each of the first three families possess mainly bi- or multilocular ovaries in a gynoecium with a long synascidiate, but very short symplicate zone, where the ovules are inserted at their transition, the so-called cross-zone (or "Querzone"). In gynoecia of the Pittosporaceae, the symplicate is much longer than the synascidiate zone, and the ovules are arranged along the first. Members of the latter family consequently have [[Locule|unilocular]] ovaries with a single cavity between adjacent carpels. | 788 | Apiales | [
"Apiales",
"Angiosperm orders",
"Taxa named by Takenoshin Nakai"
] | [] |
[] | '''Asterales''' is an [[Order (biology)|order]] of [[dicotyledon]] [[flowering plant]] that includes the large [[Family (biology)|family]] [[Asteraceae]] (or Compositae) known for composite flowers made of [[Floret#floret|florets]], and ten families related to the Asteraceae. The order is a [[Cosmopolitan distribution|cosmopolite]] (plants found throughout most of the world including desert and frigid zones), and includes mostly [[Herbaceous plant|herbaceous]] species, although a small number of trees (such as the [[Lobelia deckenii|giant Lobelia]] and the [[Dendrosenecio|giant Senecio]]) and [[shrub]] are also present. Asterales are organisms that seem to have evolved from one common [[ancestor]]. Asterales share characteristics on [[Morphology (biology)|morphological]] and biochemical levels. [[Synapomorphies]] (a character that is shared by two or more groups through evolutionary development) include the presence in the plants of [[oligosaccharide]] [[inulin]], a nutrient storage molecule used instead of [[starch]]; and unique [[stamen]] morphology. The stamens are usually found around the [[Gynoecium|style]], either aggregated densely or fused into a tube, probably an [[adaptation]] in association with the plunger (brush; or secondary) [[pollination]] that is common among the families of the order, wherein pollen is collected and stored on the length of the pistil. | 789 | Asterales | [
"Asterales",
"Angiosperm orders"
] | [] |
[
"Taxonomy"
] | The name and order Asterales is botanically venerable, dating back to at least 1926 in the [[Hutchinson system|Hutchinson system of plant taxonomy]] when it contained only five families, of which only two are retained in the APG III classification. Under the [[Cronquist system]] of taxonomic classification of flowering plants, [[Asteraceae]] was the only family in the group, but newer systems (such as [[APG II system|APG II]] and [[APG III system|APG III]]) have expanded it to 11. In the classification system of [[Rolf Dahlgren|Dahlgren]] the Asterales were in the [[superorder]] Asteriflorae (also called Asteranae). The order '''Asterales''' currently includes 11 families, the largest of which are the [[Asteraceae]], with about 25,000 species, and the [[Campanulaceae]] ("bellflowers"), with about 2,000 species. The remaining families count together for less than 1500 species. The two large families are cosmopolitan, with many of their species found in the Northern Hemisphere, and the smaller families are usually confined to Australia and the adjacent areas, or sometimes South America. Only the Asteraceae have composite flower heads; the other families do not, but share other characteristics such as storage of inulin that define the 11 families as more closely related to each other than to other plant families or orders such as the [[rosids]]. The phylogenetic tree according to APG III for the Campanulid clade is as below. | 789 | Asterales | [
"Asterales",
"Angiosperm orders"
] | [] |
[
"Biogeography"
] | The core Asterales are Stylidiaceae (six [[Genus|genera]]), APA [[clade]] (Alseuosmiaceae, Phellinaceae and Argophyllaceae, together 7 genera), MGCA clade (Menyanthaceae, Goodeniaceae, Calyceraceae, in total twenty genera), and Asteraceae (about sixteen hundred genera). Other Asterales are Rousseaceae (four genera), Campanulaceae (eighty four genera) and Pentaphragmataceae (one genus). All Asterales families are represented in the Southern Hemisphere; however, Asteraceae and Campanulaceae are cosmopolitan and Menyanthaceae nearly so. | 789 | Asterales | [
"Asterales",
"Angiosperm orders"
] | [] |
[
"Evolution"
] | Although most extant species of Asteraceae are herbaceous, the examination of the basal members in the family suggests that the common ancestor of the family was an arborescent plant, a tree or shrub, perhaps adapted to dry conditions, radiating from South America. Less can be said about the Asterales themselves with certainty, although since several families in Asterales contain trees, the ancestral member is most likely to have been a tree or shrub. Because all clades are represented in the southern hemisphere but many not in the northern hemisphere, it is natural to conjecture that there is a common southern origin to them. Asterales are [[angiosperms]], flowering plants that appeared about 140 million years ago. The Asterales order probably originated in the [[Cretaceous]] (145 – 66 [[Mya (unit)#Symbols y and yr|Mya]]) on the supercontinent [[Gondwana]] which broke up from 184 – 80 Mya, forming the area that is now Australia, South America, Africa, India and Antarctica. Asterales contain about 14% of [[eudicot]] diversity. From an analysis of relationships and diversities within the Asterales and with their superorders, estimates of the age of the beginning of the Asterales have been made, which range from 116 Mya to 82Mya. However few fossils have been found, of the Menyanthaceae-Asteraceae clade in the [[Oligocene]], about 29 Mya. Fossil evidence of the Asterales is rare and belongs to rather recent epochs, so the precise estimation of the order's age is quite difficult. An Oligocene (34 – 23 Mya) pollen is known for Asteraceae and Goodeniaceae, and seeds from Oligocene and [[Miocene]] (23 – 5.3 Mya) are known for Menyanthaceae and Campanulaceae respectively. | 789 | Asterales | [
"Asterales",
"Angiosperm orders"
] | [] |
[
"Economic importance"
] | The Asterales, by dint of being a super-set of the family Asteraceae, include some species grown for food, including the [[sunflower]] (''Helianthus annuus''), lettuce (''Lactuca sativa'') and [[chicory]] (''Cichorium''). Many are also used as spices and traditional medicines. Asterales are common plants and have many known uses. For example, [[pyrethrum]] (derived from Old World members of the genus ''Chrysanthemum'') is a natural insecticide with minimal environmental impact. [[Artemisia (genus)|Wormwood]], derived from a genus that includes the [[sagebrush]], is used as a source of flavoring for [[absinthe]], a bitter classical liquor of European origin. | 789 | Asterales | [
"Asterales",
"Angiosperm orders"
] | [] |
[] | An '''asteroid''' is a [[minor planet]] of the [[Solar System#Inner solar system|inner Solar System]]. Historically, these terms have been applied to any astronomical object orbiting the [[Sun]] that did not resolve into a disc in a telescope and was not observed to have characteristics of an active [[comet]] such as a [[Comet tail|tail]]. As [[Distant minor planet|minor planets in the outer Solar System]] were discovered that were found to have [[Volatiles|volatile]]-rich surfaces similar to comets, these came to be distinguished from the objects found in the main [[asteroid belt]]. The term "asteroid" refers to the minor planets of the inner Solar System, including those co-orbital with [[Jupiter]]. Larger asteroids are often called '''planetoids'''. | 791 | Asteroid | [
"Asteroids",
"Minor planets"
] | [
"Aten asteroid",
"Centaur (minor planet)",
"Category:Asteroids",
"List of minor planets",
"ʻOumuamua",
"Near Earth Object Surveillance Satellite",
"Category:Asteroid groups and families",
"Apollo asteroid",
"Category:Binary asteroids",
"Amor asteroid",
"Minor planet",
"''Dawn'' (spacecraft)",
"Asteroid impact avoidance",
"Lost minor planet",
"Mesoplanet",
"List of minor planets named after people",
"NEOShield",
"Dwarf planet",
"List of possible impact structures on Earth",
"''Marco Polo'' (spacecraft)",
"List of minor planets named after places",
"Impact event",
"Atira asteroid",
"Chang'e 2 lunar orbiter",
"Constellation program",
"Active asteroid",
"List of impact craters on Earth",
"List of exceptional asteroids",
"''Rosetta'' (spacecraft)",
"Near-Earth object",
"List of asteroid close approaches to Earth",
"Pioneer 10",
"BOOTES",
"Asteroid Day",
"Meanings of minor planet names"
] |
[
"Overview"
] | Millions of asteroids exist: many are shattered remnants of [[planetesimal]], bodies within the young Sun's [[solar nebula]] that never grew large enough to become [[planet]]. The vast majority of known asteroids orbit within the main asteroid belt located between the orbits of [[Mars]] and Jupiter, or are co-orbital with Jupiter (the [[Jupiter trojan]]). However, other orbital families exist with significant populations, including the [[near-Earth object]]. Individual asteroids are classified by their characteristic [[Emission spectrum|spectra]], with the majority falling into three main groups: [[C-type asteroid|C-type]], [[M-type asteroid|M-type]], and [[S-type asteroid|S-type]]. These were named after and are generally identified with [[Carbon|carbon-rich]], [[metal]], and [[silicate]] (stony) compositions, respectively. The sizes of asteroids varies greatly; the largest, [[Ceres (dwarf planet)|Ceres]], is almost across and massive enough to qualify as a [[dwarf planet]]. Asteroids are somewhat arbitrarily differentiated from [[comet]] and [[meteoroid]]. In the case of comets, the difference is one of composition: while asteroids are mainly composed of mineral and rock, comets are primarily composed of dust and ice. Furthermore, asteroids formed closer to the sun, preventing the development of cometary ice. The difference between asteroids and meteoroids is mainly one of size: meteoroids have a diameter of one meter or less, whereas asteroids have a diameter of greater than one meter. Finally, meteoroids can be composed of either cometary or asteroidal materials. Only one asteroid, [[4 Vesta]], which has a relatively [[Albedo|reflective surface]], is normally visible to the naked eye, and this is only in very dark skies when it is favorably positioned. Rarely, small asteroids passing close to Earth may be visible to the naked eye for a short time. , the [[Minor Planet Center]] had data on 930,000 minor planets in the inner and outer Solar System, of which about 545,000 had enough information to be given numbered designations. The United Nations declared 30 June as International [[Asteroid Day]] to educate the public about asteroids. The date of International Asteroid Day commemorates the anniversary of the [[Tunguska asteroid impact over Siberia]], Russian Federation, on 30 June 1908. In April 2018, the [[B612 Foundation]] reported "It is 100 percent certain we'll be hit [by a devastating asteroid], but we're not 100 percent sure when." Also in 2018, [[physicist]] [[Stephen Hawking]], in his final book ''[[Brief Answers to the Big Questions]]'', considered an asteroid collision to be the biggest threat to the planet. In June 2018, the US [[National Science and Technology Council]] warned that America is unprepared for an asteroid impact event, and has developed and released the ''"National Near-Earth Object Preparedness Strategy Action Plan"'' to better prepare. According to expert testimony in the [[United States Congress]] in 2013, [[NASA]] would require at least five years of preparation before a mission to intercept an asteroid could be launched. | 791 | Asteroid | [
"Asteroids",
"Minor planets"
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"List of exceptional asteroids",
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"Near-Earth object",
"List of asteroid close approaches to Earth",
"Pioneer 10",
"BOOTES",
"Asteroid Day",
"Meanings of minor planet names"
] |
[
"Discovery"
] | The first asteroid to be discovered, [[Ceres (dwarf planet)|Ceres]], was originally considered to be a new planet. This was followed by the discovery of other similar bodies, which, with the equipment of the time, appeared to be points of light, like stars, showing little or no planetary disc, though readily distinguishable from stars due to their apparent motions. This prompted the astronomer [[William Herschel|Sir William Herschel]] to propose the term "asteroid", coined in Greek as ἀστεροειδής, or ''asteroeidēs'', meaning 'star-like, star-shaped', and derived from the Ancient Greek ''astēr'' 'star, planet'. In the early second half of the nineteenth century, the terms "asteroid" and "planet" (not always qualified as "minor") were still used interchangeably. Discovery timeline: (-) 10 by 1849 (-) [[Ceres (dwarf planet)|1 Ceres]], 1801 (-) [[2 Pallas]] 1802 (-) [[3 Juno]] 1804 (-) [[4 Vesta]] 1807 (-) [[5 Astraea]] 1845 (-) ''in 1846, planet Neptune was discovered'' (-) [[6 Hebe]] July 1847 (-) [[7 Iris]] August 1847 (-) [[8 Flora]] October 1847 (-) [[9 Metis]] 25 April 1848 (-) [[10 Hygiea]] 12 April 1849 ''tenth asteroid discovered'' (-) 100 asteroids by 1868 (-) 1,000 by 1921 (-) 10,000 by 1989 (-) 100,000 by 2005 (-) 1,000,000 by 2020 | 791 | Asteroid | [
"Asteroids",
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"Pioneer 10",
"BOOTES",
"Asteroid Day",
"Meanings of minor planet names"
] |
[
"Discovery",
"Historical methods"
] | Asteroid discovery methods have dramatically improved over the past two centuries. In the last years of the 18th century, Baron [[Franz Xaver von Zach]] organized a group of 24 astronomers to search the sky for the missing planet predicted at about 2.8 [[Astronomical unit|AU]] from the Sun by the [[Titius-Bode law]], partly because of the discovery, by Sir [[William Herschel]] in 1781, of the planet [[Uranus]] at the distance predicted by the law. This task required that hand-drawn sky charts be prepared for all stars in the [[zodiac]] band down to an agreed-upon limit of faintness. On subsequent nights, the sky would be charted again and any moving object would, hopefully, be spotted. The expected motion of the missing planet was about 30 seconds of arc per hour, readily discernible by observers. The first object, [[Ceres (dwarf planet)|Ceres]], was not discovered by a member of the group, but rather by accident in 1801 by [[Giuseppe Piazzi]], director of the observatory of [[Palermo]] in [[Sicily]]. He discovered a new star-like object in [[Taurus (constellation)|Taurus]] and followed the displacement of this object during several nights. Later that year, [[Carl Friedrich Gauss]] used these observations to calculate the orbit of this unknown object, which was found to be between the planets [[Mars]] and [[Jupiter]]. Piazzi named it after [[Ceres (Roman mythology)|Ceres]], the Roman goddess of agriculture. Three other asteroids ([[2 Pallas]], [[3 Juno]], and [[4 Vesta]]) were discovered over the next few years, with Vesta found in 1807. After eight more years of fruitless searches, most astronomers assumed that there were no more and abandoned any further searches. However, [[Karl Ludwig Hencke]] persisted, and began searching for more asteroids in 1830. Fifteen years later, he found [[5 Astraea]], the first new asteroid in 38 years. He also found [[6 Hebe]] less than two years later. After this, other astronomers joined in the search and at least one new asteroid was discovered every year after that (except the wartime year 1945). Notable asteroid hunters of this early era were [[John Russell Hind|J.R. Hind]], [[Annibale de Gasparis|A. de Gasparis]], [[Karl Theodor Robert Luther|R. Luther]], [[Hermann Mayer Salomon Goldschmidt|H.M.S. Goldschmidt]], [[Jean Chacornac|J. Chacornac]], [[James Ferguson (American astronomer)|J. Ferguson]], [[Norman Robert Pogson|N.R. Pogson]], [[Ernst Wilhelm Leberecht Tempel|E.W. Tempel]], [[James Craig Watson|J.C. Watson]], [[Christian Heinrich Friedrich Peters|C.H.F. Peters]], [[Alphonse Louis Nicolas Borrelly|A. Borrelly]], [[Johann Palisa|J. Palisa]], [[Paul Henry and Prosper Henry|the Henry brothers]] and [[Auguste Charlois|A. Charlois]]. In 1891, [[Maximilian Franz Joseph Cornelius Wolf|Max Wolf]] pioneered the use of [[astrophotography]] to detect asteroids, which appeared as short streaks on long-exposure photographic plates. This dramatically increased the rate of detection compared with earlier visual methods: Wolf alone discovered 248 asteroids, beginning with [[323 Brucia]], whereas only slightly more than 300 had been discovered up to that point. It was known that there were many more, but most astronomers did not bother with them, some calling them "vermin of the skies", a phrase variously attributed to [[Eduard Suess|E. Suess]] and [[Edmund Weiss|E. Weiss]]. Even a century later, only a few thousand asteroids were identified, numbered and named. | 791 | Asteroid | [
"Asteroids",
"Minor planets"
] | [
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"Centaur (minor planet)",
"Category:Asteroids",
"List of minor planets",
"ʻOumuamua",
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"Near-Earth object",
"List of asteroid close approaches to Earth",
"Pioneer 10",
"BOOTES",
"Asteroid Day",
"Meanings of minor planet names"
] |
[
"Discovery",
"Manual methods of the 1900s and modern reporting"
] | Until 1998, asteroids were discovered by a four-step process. First, a region of the sky was [[Astrophotography|photographed]] by a wide-field [[telescope]], or [[astrograph]]. Pairs of photographs were taken, typically one hour apart. Multiple pairs could be taken over a series of days. Second, the two films or [[photographic plate|plates]] of the same region were viewed under a [[stereoscope]]. Any body in orbit around the Sun would move slightly between the pair of films. Under the stereoscope, the image of the body would seem to float slightly above the background of stars. Third, once a moving body was identified, its location would be measured precisely using a digitizing microscope. The location would be measured relative to known star locations. These first three steps do not constitute asteroid discovery: the observer has only found an apparition, which gets a [[provisional designation in astronomy|provisional designation]], made up of the year of discovery, a letter representing the half-month of discovery, and finally a letter and a number indicating the discovery's sequential number (example: ). The last step of discovery is to send the locations and time of observations to the [[Minor Planet Center]], where computer programs determine whether an apparition ties together earlier apparitions into a single orbit. If so, the object receives a catalogue number and the observer of the first apparition with a calculated orbit is declared the discoverer, and granted the honor of naming the object subject to the approval of the [[International Astronomical Union]]. | 791 | Asteroid | [
"Asteroids",
"Minor planets"
] | [
"Aten asteroid",
"Centaur (minor planet)",
"Category:Asteroids",
"List of minor planets",
"ʻOumuamua",
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"List of exceptional asteroids",
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"Near-Earth object",
"List of asteroid close approaches to Earth",
"Pioneer 10",
"BOOTES",
"Asteroid Day",
"Meanings of minor planet names"
] |
[
"Discovery",
"Computerized methods"
] | There is increasing interest in identifying asteroids whose orbits cross [[Earth]]'s, and that could, given enough time, collide with Earth ''(see [[List of Earth-crossing minor planets|Earth-crosser asteroids]])''. The three most important groups of [[near-Earth asteroid]] are the [[Apollo asteroid|Apollos]], [[Amor asteroid|Amors]], and [[Aten asteroid|Atens]]. Various [[asteroid deflection strategies]] have been proposed, as early as the 1960s. The [[near-Earth object|near-Earth]] asteroid [[433 Eros]] had been discovered as long ago as 1898, and the 1930s brought a flurry of similar objects. In order of discovery, these were: [[1221 Amor]], [[1862 Apollo]], [[2101 Adonis]], and finally [[69230 Hermes]], which approached within 0.005 [[Astronomical unit|AU]] of [[Earth]] in 1937. Astronomers began to realize the possibilities of Earth impact. Two events in later decades increased the alarm: the increasing acceptance of the [[Alvarez hypothesis]] that an [[impact event]] resulted in the [[Cretaceous–Paleogene extinction event|Cretaceous–Paleogene extinction]], and the 1994 observation of [[Comet Shoemaker-Levy 9]] crashing into [[Jupiter]]. The U.S. military also declassified the information that its [[military satellite]], built to [[detect nuclear explosions]], had detected hundreds of upper-atmosphere impacts by objects ranging from one to ten meters across. All these considerations helped spur the launch of highly efficient surveys that consist of charge-coupled device ([[Charge-coupled device|CCD]]) cameras and computers directly connected to telescopes. , it was estimated that 89% to 96% of near-Earth asteroids one kilometer or larger in diameter had been discovered. A list of teams using such systems includes: (-) [[Lincoln Near-Earth Asteroid Research]] (LINEAR) (-) [[Near-Earth Asteroid Tracking]] (NEAT) (-) [[Spacewatch]] (-) [[LONEOS|Lowell Observatory Near-Earth-Object Search]] (LONEOS) (-) [[Catalina Sky Survey]] (CSS) (-) [[Pan-STARRS]] (-) [[NEOWISE]] (-) [[Asteroid Terrestrial-impact Last Alert System]] (ATLAS) (-) [[Campo Imperatore Near-Earth Object Survey]] (CINEOS) (-) [[Japanese Spaceguard Association]] (-) [[Asiago-DLR Asteroid Survey]] (ADAS) , the LINEAR system alone has discovered 147,132 asteroids. Among all the surveys, 19,266 near-Earth asteroids have been discovered including almost 900 more than in diameter. | 791 | Asteroid | [
"Asteroids",
"Minor planets"
] | [
"Aten asteroid",
"Centaur (minor planet)",
"Category:Asteroids",
"List of minor planets",
"ʻOumuamua",
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"Apollo asteroid",
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"List of exceptional asteroids",
"''Rosetta'' (spacecraft)",
"Near-Earth object",
"List of asteroid close approaches to Earth",
"Pioneer 10",
"BOOTES",
"Asteroid Day",
"Meanings of minor planet names"
] |
[
"Terminology"
] | [[file:Ceres and Vesta, Moon size comparison.jpg|thumb|The largest asteroid in the previous image, [[4 Vesta|Vesta]] (left), with [[Ceres (dwarf planet)|Ceres]] (center) and the [[Moon]] (right) shown to scale.]] Traditionally, small bodies orbiting the Sun were classified as [[comet]], asteroids, or [[meteoroid]], with anything smaller than one meter across being called a meteoroid. Beech and Steel's 1995 paper proposed a meteoroid definition including size limits. The term "asteroid", from the Greek word for "star-like", never had a formal definition, with the broader term [[minor planet]] being preferred by the [[International Astronomical Union]]. However, following the discovery of asteroids below ten meters in size, Rubin and Grossman's 2010 paper revised the previous definition of meteoroid to objects between 10 [[micrometre|µm]] and 1 meter in size in order to maintain the distinction between asteroids and meteoroids. The smallest asteroids discovered (based on [[Absolute magnitude#Solar System bodies (H)|absolute magnitude]] ''H'') are with and with both with an estimated size of about 1 meter. In 2006, the term "[[small Solar System body]]" was also introduced to cover both most minor planets and comets. Other languages prefer "planetoid" (Greek for "planet-like"), and this term is occasionally used in English especially for larger minor planets such as the [[dwarf planet]] as well as an alternative for asteroids since they are not star-like. The word "[[planetesimal]]" has a similar meaning, but refers specifically to the small building blocks of the planets that existed when the Solar System was forming. The term "planetule" was coined by the geologist [[William Daniel Conybeare]] to describe minor planets, but is not in common use. The three largest objects in the asteroid belt, [[Ceres (dwarf planet)|Ceres]], [[2 Pallas|Pallas]], and [[4 Vesta|Vesta]], grew to the stage of [[protoplanet]]. Ceres is a [[dwarf planet]], the only one in the inner Solar System. When found, asteroids were seen as a class of objects distinct from comets, and there was no unified term for the two until "small Solar System body" was coined in 2006. The main difference between an asteroid and a comet is that a comet shows a coma due to [[Outgassing|sublimation]] of near-surface ices by solar radiation. A few objects have ended up being dual-listed because they were first classified as minor planets but later showed evidence of cometary activity. Conversely, some (perhaps all) comets are eventually depleted of their surface [[volatiles|volatile ices]] and become asteroid-like. A further distinction is that comets typically have more eccentric orbits than most asteroids; most "asteroids" with notably eccentric orbits are probably dormant or extinct comets. | 791 | Asteroid | [
"Asteroids",
"Minor planets"
] | [
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"Centaur (minor planet)",
"Category:Asteroids",
"List of minor planets",
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"List of exceptional asteroids",
"''Rosetta'' (spacecraft)",
"Near-Earth object",
"List of asteroid close approaches to Earth",
"Pioneer 10",
"BOOTES",
"Asteroid Day",
"Meanings of minor planet names"
] |
[
"Terminology"
] | For almost two centuries, from the discovery of [[Ceres (dwarf planet)|Ceres]] in 1801 until the discovery of the first [[centaur (minor planet)|centaur]], [[2060 Chiron|Chiron]] in 1977, all known asteroids spent most of their time at or within the orbit of Jupiter, though a few such as [[944 Hidalgo|Hidalgo]] ventured far beyond Jupiter for part of their orbit. Those located between the orbits of Mars and Jupiter were known for many years simply as The Asteroids. When astronomers started finding more small bodies that permanently resided further out than Jupiter, now called [[centaur (minor planet)|centaurs]], they numbered them among the traditional asteroids, though there was debate over whether they should be considered asteroids or as a new type of object. Then, when the first [[trans-Neptunian object]] (other than [[Pluto]]), [[15760 Albion|Albion]], was discovered in 1992, and especially when large numbers of similar objects started turning up, new terms were invented to sidestep the issue: [[Kuiper belt|Kuiper-belt object]], [[trans-Neptunian object]], [[scattered-disc object]], and so on. These inhabit the cold outer reaches of the Solar System where ices remain solid and comet-like bodies are not expected to exhibit much cometary activity; if centaurs or trans-Neptunian objects were to venture close to the Sun, their volatile ices would sublimate, and traditional approaches would classify them as comets and not asteroids. The innermost of these are the [[Kuiper belt|Kuiper-belt objects]], called "objects" partly to avoid the need to classify them as asteroids or comets. They are thought to be predominantly comet-like in composition, though some may be more akin to asteroids. Furthermore, most do not have the highly eccentric orbits associated with comets, and the ones so far discovered are larger than traditional [[Comet nucleus|comet nuclei]]. (The much more distant [[Oort cloud]] is hypothesized to be the main reservoir of dormant comets.) Other recent observations, such as the analysis of the cometary dust collected by the [[Stardust (spacecraft)|''Stardust'']] probe, are increasingly blurring the distinction between comets and asteroids, suggesting "a continuum between asteroids and comets" rather than a sharp dividing line. The minor planets beyond Jupiter's orbit are sometimes also called "asteroids", especially in popular presentations. However, it is becoming increasingly common for the term "asteroid" to be restricted to minor planets of the inner Solar System. Therefore, this article will restrict itself for the most part to the classical asteroids: objects of the [[asteroid belt]], [[Jupiter trojan]], and [[near-Earth object]]. When the IAU introduced the class [[Small Solar System body|small Solar System bodies]] in 2006 to include most objects previously classified as minor planets and comets, they created the class of [[dwarf planet]] for the largest minor planets – those that have enough mass to have become ellipsoidal under their own gravity. According to the IAU, "the term 'minor planet' may still be used, but generally, the term 'Small Solar System Body' will be preferred." Currently only the largest object in the asteroid belt, [[Ceres (dwarf planet)|Ceres]], at about across, has been placed in the dwarf planet category. | 791 | Asteroid | [
"Asteroids",
"Minor planets"
] | [
"Aten asteroid",
"Centaur (minor planet)",
"Category:Asteroids",
"List of minor planets",
"ʻOumuamua",
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"Category:Asteroid groups and families",
"Apollo asteroid",
"Category:Binary asteroids",
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"Minor planet",
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"Near-Earth object",
"List of asteroid close approaches to Earth",
"Pioneer 10",
"BOOTES",
"Asteroid Day",
"Meanings of minor planet names"
] |
[
"Formation"
] | It is thought that [[planetesimal]] in the asteroid belt evolved much like the rest of the [[solar nebula]] until Jupiter neared its current mass, at which point excitation from [[orbital resonance]] with Jupiter ejected over 99% of planetesimals in the belt. Simulations and a discontinuity in spin rate and spectral properties suggest that asteroids larger than approximately in diameter [[Accretion (astrophysics)|accreted]] during that early era, whereas smaller bodies are fragments from collisions between asteroids during or after the Jovian disruption. Ceres and Vesta grew large enough to melt and [[Planetary differentiation|differentiate]], with heavy metallic elements sinking to the core, leaving rocky minerals in the crust. In the [[Nice model]], many [[Kuiper belt|Kuiper-belt objects]] are captured in the outer asteroid belt, at distances greater than 2.6 AU. Most were later ejected by Jupiter, but those that remained may be the [[D-type asteroid]], and possibly include Ceres. | 791 | Asteroid | [
"Asteroids",
"Minor planets"
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"Aten asteroid",
"Centaur (minor planet)",
"Category:Asteroids",
"List of minor planets",
"ʻOumuamua",
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"Near-Earth object",
"List of asteroid close approaches to Earth",
"Pioneer 10",
"BOOTES",
"Asteroid Day",
"Meanings of minor planet names"
] |
[
"Distribution within the Solar System"
] | Various dynamical groups of asteroids have been discovered orbiting in the inner Solar System. Their orbits are perturbed by the gravity of other bodies in the Solar System and by the [[Yarkovsky effect]]. Significant populations include: | 791 | Asteroid | [
"Asteroids",
"Minor planets"
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"Category:Asteroids",
"List of minor planets",
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"List of possible impact structures on Earth",
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"Chang'e 2 lunar orbiter",
"Constellation program",
"Active asteroid",
"List of impact craters on Earth",
"List of exceptional asteroids",
"''Rosetta'' (spacecraft)",
"Near-Earth object",
"List of asteroid close approaches to Earth",
"Pioneer 10",
"BOOTES",
"Asteroid Day",
"Meanings of minor planet names"
] |
[
"Distribution within the Solar System",
"Asteroid belt"
] | The majority of known asteroids orbit within the asteroid belt between the orbits of [[Mars]] and [[Jupiter]], generally in relatively low-[[orbital eccentricity|eccentricity]] (i.e. not very elongated) orbits. This belt is now estimated to contain between 1.1 and 1.9 million asteroids larger than in diameter, and millions of smaller ones. These asteroids may be remnants of the [[protoplanetary disk]], and in this region the [[accretion (astrophysics)|accretion]] of [[planetesimal]] into planets during the formative period of the Solar System was prevented by large gravitational perturbations by [[Jupiter]]. | 791 | Asteroid | [
"Asteroids",
"Minor planets"
] | [
"Aten asteroid",
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"Category:Asteroids",
"List of minor planets",
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"List of minor planets named after places",
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"Atira asteroid",
"Chang'e 2 lunar orbiter",
"Constellation program",
"Active asteroid",
"List of impact craters on Earth",
"List of exceptional asteroids",
"''Rosetta'' (spacecraft)",
"Near-Earth object",
"List of asteroid close approaches to Earth",
"Pioneer 10",
"BOOTES",
"Asteroid Day",
"Meanings of minor planet names"
] |
[
"Distribution within the Solar System",
"Trojans"
] | [[Trojan (astronomy)|Trojans]] are populations that share an orbit with a larger planet or moon, but do not collide with it because they orbit in one of the two [[Lagrangian point]] of stability, [[Trojan points|L4 and L5]], which lie 60° ahead of and behind the larger body. The most significant population of trojans are the [[Jupiter trojan]]. Although fewer Jupiter trojans have been discovered (), it is thought that they are as numerous as the asteroids in the asteroid belt. Trojans have been found in the orbits of other planets, including [[Venus trojan|Venus]], [[Earth trojan|Earth]], [[Mars trojan|Mars]], [[Uranus trojan|Uranus]], and [[Neptune trojan|Neptune]]. | 791 | Asteroid | [
"Asteroids",
"Minor planets"
] | [
"Aten asteroid",
"Centaur (minor planet)",
"Category:Asteroids",
"List of minor planets",
"ʻOumuamua",
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"Apollo asteroid",
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"Near-Earth object",
"List of asteroid close approaches to Earth",
"Pioneer 10",
"BOOTES",
"Asteroid Day",
"Meanings of minor planet names"
] |
[
"Distribution within the Solar System",
"Near-Earth asteroids"
] | Near-Earth asteroids, or NEAs, are asteroids that have orbits that pass close to that of Earth. Asteroids that actually cross Earth's orbital path are known as ''Earth-crossers''. , 14,464 near-Earth asteroids are known and approximately 900-1,000 have a diameter of over one kilometer. | 791 | Asteroid | [
"Asteroids",
"Minor planets"
] | [
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"Centaur (minor planet)",
"Category:Asteroids",
"List of minor planets",
"ʻOumuamua",
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"List of asteroid close approaches to Earth",
"Pioneer 10",
"BOOTES",
"Asteroid Day",
"Meanings of minor planet names"
] |
[
"Characteristics",
"Size distribution"
] | Asteroids vary greatly in size, from almost for the largest down to rocks just 1 meter across. The three largest are very much like miniature planets: they are roughly spherical, have at least partly differentiated interiors, and are thought to be surviving [[protoplanet]]. The vast majority, however, are much smaller and are irregularly shaped; they are thought to be either battered [[planetesimal]] or fragments of larger bodies. The [[dwarf planet]] [[Ceres (dwarf planet)|Ceres]] is by far the largest asteroid, with a diameter of . The next largest are [[4 Vesta]] and [[2 Pallas]], both with diameters of just over . Vesta is the only main-belt asteroid that can, on occasion, be visible to the naked eye. On some rare occasions, a near-Earth asteroid may briefly become visible without technical aid; see [[99942 Apophis]]. The mass of all the objects of the [[asteroid belt]], lying between the orbits of [[Mars]] and [[Jupiter]], is estimated to be in the range of , about 4% of the mass of the Moon. Of this, [[Ceres (dwarf planet)|Ceres]] comprises , about a third of the total. Adding in the next three most massive objects, [[4 Vesta|Vesta]] (9%), [[2 Pallas|Pallas]] (7%), and [[10 Hygiea|Hygiea]] (3%), brings this figure up to half, whereas the three most-massive asteroids after that, [[511 Davida]] (1.2%), [[704 Interamnia]] (1.0%), and [[52 Europa]] (0.9%), constitute only another 3%. The number of asteroids increases rapidly as their individual masses decrease. The number of asteroids decreases markedly with size. Although this generally follows a [[power law]], there are 'bumps' at and , where more asteroids than expected from a [[logarithmic distribution]] are found. | 791 | Asteroid | [
"Asteroids",
"Minor planets"
] | [
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"Category:Asteroids",
"List of minor planets",
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"Pioneer 10",
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"Meanings of minor planet names"
] |
[
"Characteristics",
"Size distribution",
"Largest asteroids"
] | Although their location in the asteroid belt excludes them from planet status, the three largest objects, [[Ceres (dwarf planet)|Ceres]], [[4 Vesta|Vesta]], and [[2 Pallas|Pallas]], are intact [[protoplanet]] that share many characteristics common to planets, and are atypical compared to the majority of irregularly shaped asteroids. The fourth-largest asteroid, [[10 Hygiea|Hygiea]], appears nearly spherical although it may have an undifferentiated interior, like the majority of asteroids. Between them, the four largest asteroids constitute half the mass of the asteroid belt. Ceres is the only asteroid with a fully ellipsoidal shape and hence the only one that is a [[dwarf planet]]. It has a much higher [[Absolute magnitude#Solar System bodies (H)|absolute magnitude]] than the other asteroids, of around 3.32, and may possess a surface layer of ice. Like the planets, Ceres is differentiated: it has a crust, a mantle and a core. No meteorites from Ceres have been found on Earth. Vesta, too, has a differentiated interior, though it formed inside the Solar System's [[Frost line (astrophysics)|frost line]], and so is devoid of water; its composition is mainly of basaltic rock with minerals such as olivine. Aside from the large crater at its southern pole, [[Rheasilvia]], Vesta also has an ellipsoidal shape. Vesta is the parent body of the [[Vestian family]] and other [[V-type asteroid]], and is the source of the [[HED meteorite]], which constitute 5% of all meteorites on Earth. Pallas is unusual in that, like [[Uranus]], it rotates on its side, with its axis of rotation tilted at high angles to its orbital plane. Its composition is similar to that of Ceres: high in carbon and silicon, and perhaps partially differentiated. Pallas is the parent body of the [[Palladian family]] of asteroids. Hygiea is the largest carbonaceous asteroid and, unlike the other largest asteroids, lies relatively close to the [[plane of the ecliptic]]. It is the largest member and presumed parent body of the [[Hygiean family]] of asteroids. Because there is no sufficiently large crater on the surface to be the source of that family, as there is on Vesta, it is thought that Hygiea may have been completely disrupted in the collision that formed the Hygiean family and recoalesced after losing a bit less than 2% of its mass. Observations taken with the [[Very Large Telescope]]'s [[VLT-SPHERE|SPHERE]] imager in 2017 and 2018, and announced in late 2019, revealed that Hygiea has a nearly spherical shape, which is consistent both with it being in [[hydrostatic equilibrium]] (and thus a [[dwarf planet]]), or formerly being in hydrostatic equilibrium, or with being disrupted and recoalescing. | 791 | Asteroid | [
"Asteroids",
"Minor planets"
] | [
"Aten asteroid",
"Centaur (minor planet)",
"Category:Asteroids",
"List of minor planets",
"ʻOumuamua",
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"Apollo asteroid",
"Category:Binary asteroids",
"Amor asteroid",
"Minor planet",
"''Dawn'' (spacecraft)",
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"Lost minor planet",
"Mesoplanet",
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"NEOShield",
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"List of minor planets named after places",
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"Chang'e 2 lunar orbiter",
"Constellation program",
"Active asteroid",
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"List of exceptional asteroids",
"''Rosetta'' (spacecraft)",
"Near-Earth object",
"List of asteroid close approaches to Earth",
"Pioneer 10",
"BOOTES",
"Asteroid Day",
"Meanings of minor planet names"
] |
[
"Characteristics",
"Rotation"
] | Measurements of the rotation rates of large asteroids in the asteroid belt show that there is an upper limit. Very few asteroids with a diameter larger than 100 meters have a rotation period smaller than 2.2 hours. For asteroids rotating faster than approximately this rate, the inertial force at the surface is greater than the gravitational force, so any loose surface material would be flung out. However, a solid object should be able to rotate much more rapidly. This suggests that most asteroids with a diameter over 100 meters are [[rubble pile]] formed through the accumulation of debris after collisions between asteroids. | 791 | Asteroid | [
"Asteroids",
"Minor planets"
] | [
"Aten asteroid",
"Centaur (minor planet)",
"Category:Asteroids",
"List of minor planets",
"ʻOumuamua",
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"List of asteroid close approaches to Earth",
"Pioneer 10",
"BOOTES",
"Asteroid Day",
"Meanings of minor planet names"
] |
[
"Characteristics",
"Composition"
] | The physical composition of asteroids is varied and in most cases poorly understood. Ceres appears to be composed of a rocky core covered by an icy mantle, where Vesta is thought to have a [[nickel-iron]] core, [[olivine]] mantle, and basaltic crust. [[10 Hygiea]], however, which appears to have a uniformly primitive composition of [[carbonaceous chondrite]], is thought to be the largest undifferentiated asteroid. Most of the smaller asteroids are thought to be piles of rubble held together loosely by gravity, though the largest are probably solid. Some asteroids have [[Asteroid moon|moons]] or are co-orbiting [[binary asteroid|binaries]]: Rubble piles, moons, binaries, and scattered [[asteroid family|asteroid families]] are thought to be the results of collisions that disrupted a parent asteroid, or, possibly, a [[disrupted planet|planet]]. Asteroids contain traces of [[amino acid]] and other organic compounds, and some speculate that asteroid impacts may have seeded the early Earth with the chemicals necessary to initiate life, or may have even brought life itself to Earth ''(also see [[panspermia]])''. In August 2011, a report, based on [[NASA]] studies with [[meteorite]] found on [[Earth]], was published suggesting [[DNA]] and [[RNA]] components ([[adenine]], [[guanine]] and related [[organic molecules]]) may have been formed on asteroids and [[comet]] in [[outer space]]. Composition is calculated from three primary sources: [[albedo]], surface spectrum, and density. The last can only be determined accurately by observing the orbits of moons the asteroid might have. So far, every asteroid with moons has turned out to be a rubble pile, a loose conglomeration of rock and metal that may be half empty space by volume. The investigated asteroids are as large as 280 km in diameter, and include [[121 Hermione]] (268×186×183 km), and [[87 Sylvia]] (384×262×232 km). Only half a dozen asteroids are [[List of notable asteroids#Largest by diameter|larger than 87 Sylvia]], though none of them have moons; however, some smaller asteroids are thought to be more massive, suggesting they may not have been disrupted, and indeed [[511 Davida]], the same size as Sylvia to within measurement error, is estimated to be two and a half times as massive, though this is highly uncertain. The fact that such large asteroids as Sylvia can be rubble piles, presumably due to disruptive impacts, has important consequences for the formation of the Solar System: Computer simulations of collisions involving solid bodies show them destroying each other as often as merging, but colliding rubble piles are more likely to merge. This means that the cores of the planets could have formed relatively quickly. On 7 October 2009, the presence of [[ice|water ice]] was confirmed on the surface of [[24 Themis]] using [[NASA]]'s [[Infrared Telescope Facility]]. The surface of the asteroid appears completely covered in ice. As this [[ice]] layer is [[Sublimation (phase transition)|sublimating]], it may be getting replenished by a reservoir of ice under the surface. Organic compounds were also detected on the surface. Scientists hypothesize that some of the first water brought to [[Earth]] was delivered by asteroid impacts after the collision that produced the [[Moon]]. The presence of ice on 24 Themis supports this theory. | 791 | Asteroid | [
"Asteroids",
"Minor planets"
] | [
"Aten asteroid",
"Centaur (minor planet)",
"Category:Asteroids",
"List of minor planets",
"ʻOumuamua",
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"Near-Earth object",
"List of asteroid close approaches to Earth",
"Pioneer 10",
"BOOTES",
"Asteroid Day",
"Meanings of minor planet names"
] |
[
"Characteristics",
"Composition"
] | In October 2013, water was detected on an extrasolar body for the first time, on an asteroid orbiting the [[white dwarf]] [[GD 61]]. On 22 January 2014, [[European Space Agency]] (ESA) scientists reported the detection, for the first definitive time, of [[water vapor]] on [[Ceres (dwarf planet)|Ceres]], the largest object in the asteroid belt. The detection was made by using the [[Far-infrared astronomy|far-infrared abilities]] of the [[Herschel Space Observatory]]. The finding is unexpected because comets, not asteroids, are typically considered to "sprout jets and plumes". According to one of the scientists, "The lines are becoming more and more blurred between comets and asteroids." In May 2016, significant asteroid data arising from the [[Wide-field Infrared Survey Explorer]] and [[Wide-field Infrared Survey Explorer#NEOWISE|NEOWISE]] missions have been questioned. Although the early original criticism had not undergone peer review, a more recent peer-reviewed study was subsequently published. In November 2019, scientists reported detecting, for the first time, [[Sugar|sugar molecules]], including [[ribose]], in [[meteorite]], suggesting that chemical processes on asteroids can produce some fundamentally essential bio-ingredients important to [[life]], and supporting the notion of an [[RNA world]] prior to a DNA-based [[Abiogenesis|origin of life]] on Earth, and possibly, as well, the notion of [[panspermia]]. Acfer 049, a meteorite discovered in Algeria in 1990, was shown in 2019 to have ice fossils inside it – the first direct evidence of water ice in the composition of asteroids. | 791 | Asteroid | [
"Asteroids",
"Minor planets"
] | [
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"Category:Asteroids",
"List of minor planets",
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"Near-Earth object",
"List of asteroid close approaches to Earth",
"Pioneer 10",
"BOOTES",
"Asteroid Day",
"Meanings of minor planet names"
] |
[
"Characteristics",
"Surface features"
] | Most asteroids outside the "[[List of exceptional asteroids#Largest by mass|big four]]" (Ceres, Pallas, Vesta, and Hygiea) are likely to be broadly similar in appearance, if irregular in shape. 50 km (31 mi) [[253 Mathilde]] is a rubble pile saturated with craters with diameters the size of the asteroid's radius, and Earth-based observations of 300 km (186 mi) [[511 Davida]], one of the largest asteroids after the big four, reveal a similarly angular profile, suggesting it is also saturated with radius-size craters. Medium-sized asteroids such as Mathilde and [[243 Ida]] that have been observed up close also reveal a deep [[regolith]] covering the surface. Of the big four, Pallas and Hygiea are practically unknown. Vesta has compression fractures encircling a radius-size crater at its south pole but is otherwise a [[spheroid]]. Ceres seems quite different in the glimpses Hubble has provided, with surface features that are unlikely to be due to simple craters and impact basins, but details will be expanded with the ''[[Dawn (spacecraft)|Dawn spacecraft]]'', which entered Ceres orbit on 6 March 2015. | 791 | Asteroid | [
"Asteroids",
"Minor planets"
] | [
"Aten asteroid",
"Centaur (minor planet)",
"Category:Asteroids",
"List of minor planets",
"ʻOumuamua",
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"List of asteroid close approaches to Earth",
"Pioneer 10",
"BOOTES",
"Asteroid Day",
"Meanings of minor planet names"
] |
[
"Characteristics",
"Color"
] | Asteroids become darker and redder with age due to [[space weathering]]. However evidence suggests most of the color change occurs rapidly, in the first hundred thousand years, limiting the usefulness of spectral measurement for determining the age of asteroids. | 791 | Asteroid | [
"Asteroids",
"Minor planets"
] | [
"Aten asteroid",
"Centaur (minor planet)",
"Category:Asteroids",
"List of minor planets",
"ʻOumuamua",
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"List of asteroid close approaches to Earth",
"Pioneer 10",
"BOOTES",
"Asteroid Day",
"Meanings of minor planet names"
] |
[
"Classification"
] | Asteroids are commonly categorized according to two criteria: the characteristics of their orbits, and features of their reflectance [[visible spectrum|spectrum]]. | 791 | Asteroid | [
"Asteroids",
"Minor planets"
] | [
"Aten asteroid",
"Centaur (minor planet)",
"Category:Asteroids",
"List of minor planets",
"ʻOumuamua",
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"Near-Earth object",
"List of asteroid close approaches to Earth",
"Pioneer 10",
"BOOTES",
"Asteroid Day",
"Meanings of minor planet names"
] |
[
"Classification",
"Orbital classification"
] | Many asteroids have been placed in groups and families based on their orbital characteristics. Apart from the broadest divisions, it is customary to name a group of asteroids after the first member of that group to be discovered. Groups are relatively loose dynamical associations, whereas families are tighter and result from the catastrophic break-up of a large parent asteroid sometime in the past. Families are more common and easier to identify within the main asteroid belt, but several small families have been reported among the [[Jupiter trojan]]. Main belt families were first recognized by [[Kiyotsugu Hirayama]] in 1918 and are often called [[Hirayama families]] in his honor. About 30–35% of the bodies in the asteroid belt belong to dynamical families each thought to have a common origin in a past collision between asteroids. A family has also been associated with the plutoid [[dwarf planet]] . | 791 | Asteroid | [
"Asteroids",
"Minor planets"
] | [
"Aten asteroid",
"Centaur (minor planet)",
"Category:Asteroids",
"List of minor planets",
"ʻOumuamua",
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"Near-Earth object",
"List of asteroid close approaches to Earth",
"Pioneer 10",
"BOOTES",
"Asteroid Day",
"Meanings of minor planet names"
] |
[
"Classification",
"Orbital classification",
"Quasi-satellites and horseshoe objects"
] | Some asteroids have unusual [[horseshoe orbit]] that are co-orbital with [[Earth]] or some other planet. Examples are [[3753 Cruithne]] and . The first instance of this type of orbital arrangement was discovered between [[Saturn]]'s moons [[Epimetheus (moon)|Epimetheus]] and [[Janus (moon)|Janus]]. Sometimes these horseshoe objects temporarily become [[quasi-satellite]] for a few decades or a few hundred years, before returning to their earlier status. Both Earth and [[Venus]] are known to have quasi-satellites. Such objects, if associated with Earth or Venus or even hypothetically [[Mercury (planet)|Mercury]], are a special class of [[Aten asteroid]]. However, such objects could be associated with outer planets as well. | 791 | Asteroid | [
"Asteroids",
"Minor planets"
] | [
"Aten asteroid",
"Centaur (minor planet)",
"Category:Asteroids",
"List of minor planets",
"ʻOumuamua",
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"Minor planet",
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"List of exceptional asteroids",
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"Near-Earth object",
"List of asteroid close approaches to Earth",
"Pioneer 10",
"BOOTES",
"Asteroid Day",
"Meanings of minor planet names"
] |
[
"Classification",
"Spectral classification"
] | In 1975, an asteroid [[Taxonomy (general)|taxonomic]] system based on [[color]], [[albedo]], and [[spectral line|spectral shape]] was developed by [[Clark R. Chapman|Chapman]], [[David Morrison (astrophysicist)|Morrison]], and [[Ben Zellner|Zellner]]. These properties are thought to correspond to the composition of the asteroid's surface material. The original classification system had three categories: [[C-type asteroid|C-types]] for dark carbonaceous objects (75% of known asteroids), [[S-type asteroid|S-types]] for stony (silicaceous) objects (17% of known asteroids) and U for those that did not fit into either C or S. This classification has since been expanded to include many other asteroid types. The number of types continues to grow as more asteroids are studied. The two most widely used taxonomies now used are the [[Tholen classification]] and [[SMASS classification]]. The former was proposed in 1984 by [[David J. Tholen]], and was based on data collected from an eight-color asteroid survey performed in the 1980s. This resulted in 14 asteroid categories. In 2002, the Small Main-Belt Asteroid Spectroscopic Survey resulted in a modified version of the Tholen taxonomy with 24 different types. Both systems have three broad categories of C, S, and X asteroids, where X consists of mostly metallic asteroids, such as the [[M-type asteroid|M-type]]. There are also several smaller classes. The proportion of known asteroids falling into the various spectral types does not necessarily reflect the proportion of all asteroids that are of that type; some types are easier to detect than others, biasing the totals. | 791 | Asteroid | [
"Asteroids",
"Minor planets"
] | [
"Aten asteroid",
"Centaur (minor planet)",
"Category:Asteroids",
"List of minor planets",
"ʻOumuamua",
"Near Earth Object Surveillance Satellite",
"Category:Asteroid groups and families",
"Apollo asteroid",
"Category:Binary asteroids",
"Amor asteroid",
"Minor planet",
"''Dawn'' (spacecraft)",
"Asteroid impact avoidance",
"Lost minor planet",
"Mesoplanet",
"List of minor planets named after people",
"NEOShield",
"Dwarf planet",
"List of possible impact structures on Earth",
"''Marco Polo'' (spacecraft)",
"List of minor planets named after places",
"Impact event",
"Atira asteroid",
"Chang'e 2 lunar orbiter",
"Constellation program",
"Active asteroid",
"List of impact craters on Earth",
"List of exceptional asteroids",
"''Rosetta'' (spacecraft)",
"Near-Earth object",
"List of asteroid close approaches to Earth",
"Pioneer 10",
"BOOTES",
"Asteroid Day",
"Meanings of minor planet names"
] |
[
"Classification",
"Spectral classification",
"Problems"
] | Originally, spectral designations were based on inferences of an asteroid's composition. However, the correspondence between spectral class and composition is not always very good, and a variety of classifications are in use. This has led to significant confusion. Although asteroids of different spectral classifications are likely to be composed of different materials, there are no assurances that asteroids within the same taxonomic class are composed of the same (or similar) materials. | 791 | Asteroid | [
"Asteroids",
"Minor planets"
] | [
"Aten asteroid",
"Centaur (minor planet)",
"Category:Asteroids",
"List of minor planets",
"ʻOumuamua",
"Near Earth Object Surveillance Satellite",
"Category:Asteroid groups and families",
"Apollo asteroid",
"Category:Binary asteroids",
"Amor asteroid",
"Minor planet",
"''Dawn'' (spacecraft)",
"Asteroid impact avoidance",
"Lost minor planet",
"Mesoplanet",
"List of minor planets named after people",
"NEOShield",
"Dwarf planet",
"List of possible impact structures on Earth",
"''Marco Polo'' (spacecraft)",
"List of minor planets named after places",
"Impact event",
"Atira asteroid",
"Chang'e 2 lunar orbiter",
"Constellation program",
"Active asteroid",
"List of impact craters on Earth",
"List of exceptional asteroids",
"''Rosetta'' (spacecraft)",
"Near-Earth object",
"List of asteroid close approaches to Earth",
"Pioneer 10",
"BOOTES",
"Asteroid Day",
"Meanings of minor planet names"
] |
[
"Naming"
] | A newly discovered asteroid is given a [[Provisional designation in astronomy|provisional designation]] (such as ) consisting of the year of discovery and an alphanumeric code indicating the [[half-month]] of discovery and the sequence within that half-month. Once an asteroid's orbit has been confirmed, it is given a number, and later may also be given a name (e.g. ). The formal naming convention uses parentheses around the number – e.g. (433) Eros – but dropping the parentheses is quite common. Informally, it is common to drop the number altogether, or to drop it after the first mention when a name is repeated in running text. In addition, names can be proposed by the asteroid's discoverer, within guidelines established by the International Astronomical Union. | 791 | Asteroid | [
"Asteroids",
"Minor planets"
] | [
"Aten asteroid",
"Centaur (minor planet)",
"Category:Asteroids",
"List of minor planets",
"ʻOumuamua",
"Near Earth Object Surveillance Satellite",
"Category:Asteroid groups and families",
"Apollo asteroid",
"Category:Binary asteroids",
"Amor asteroid",
"Minor planet",
"''Dawn'' (spacecraft)",
"Asteroid impact avoidance",
"Lost minor planet",
"Mesoplanet",
"List of minor planets named after people",
"NEOShield",
"Dwarf planet",
"List of possible impact structures on Earth",
"''Marco Polo'' (spacecraft)",
"List of minor planets named after places",
"Impact event",
"Atira asteroid",
"Chang'e 2 lunar orbiter",
"Constellation program",
"Active asteroid",
"List of impact craters on Earth",
"List of exceptional asteroids",
"''Rosetta'' (spacecraft)",
"Near-Earth object",
"List of asteroid close approaches to Earth",
"Pioneer 10",
"BOOTES",
"Asteroid Day",
"Meanings of minor planet names"
] |
[
"Naming",
"Symbols"
] | The first asteroids to be discovered were assigned iconic symbols like the ones traditionally used to designate the planets. By 1855 there were two dozen asteroid symbols, which often occurred in multiple variants. In 1851, after the fifteenth asteroid ([[15 Eunomia|Eunomia]]) had been discovered, [[Johann Franz Encke]] made a major change in the upcoming 1854 edition of the ''[[Berliner Astronomisches Jahrbuch]]'' (BAJ, ''Berlin Astronomical Yearbook''). He introduced a disk (circle), a traditional symbol for a star, as the generic symbol for an asteroid. The circle was then numbered in order of discovery to indicate a specific asteroid (although he assigned ① to the fifth, [[5 Astraea|Astraea]], while continuing to designate the first four only with their existing iconic symbols). The numbered-circle convention was quickly adopted by astronomers, and the next asteroid to be discovered ([[16 Psyche]], in 1852) was the first to be designated in that way at the time of its discovery. However, Psyche was given an iconic symbol as well, as were a few other asteroids discovered over the next few years (see chart above). [[20 Massalia]] was the first asteroid that was not assigned an iconic symbol, and no iconic symbols were created after the 1855 discovery of [[37 Fides]]. That year Astraea's number was increased to ⑤, but the first four asteroids, Ceres to Vesta, were not listed by their numbers until the 1867 edition. The circle was soon abbreviated to a pair of parentheses, which were easier to typeset and sometimes omitted altogether over the next few decades, leading to the modern convention. | 791 | Asteroid | [
"Asteroids",
"Minor planets"
] | [
"Aten asteroid",
"Centaur (minor planet)",
"Category:Asteroids",
"List of minor planets",
"ʻOumuamua",
"Near Earth Object Surveillance Satellite",
"Category:Asteroid groups and families",
"Apollo asteroid",
"Category:Binary asteroids",
"Amor asteroid",
"Minor planet",
"''Dawn'' (spacecraft)",
"Asteroid impact avoidance",
"Lost minor planet",
"Mesoplanet",
"List of minor planets named after people",
"NEOShield",
"Dwarf planet",
"List of possible impact structures on Earth",
"''Marco Polo'' (spacecraft)",
"List of minor planets named after places",
"Impact event",
"Atira asteroid",
"Chang'e 2 lunar orbiter",
"Constellation program",
"Active asteroid",
"List of impact craters on Earth",
"List of exceptional asteroids",
"''Rosetta'' (spacecraft)",
"Near-Earth object",
"List of asteroid close approaches to Earth",
"Pioneer 10",
"BOOTES",
"Asteroid Day",
"Meanings of minor planet names"
] |
[
"Exploration"
] | Until the age of [[Spaceflight|space travel]], objects in the asteroid belt were merely pinpricks of light in even the largest telescopes and their shapes and terrain remained a mystery. The best modern ground-based telescopes and the Earth-orbiting [[Hubble Space Telescope]] can resolve a small amount of detail on the surfaces of the largest asteroids, but even these mostly remain little more than fuzzy blobs. Limited information about the shapes and compositions of asteroids can be inferred from their [[light curve]] (their variation in brightness as they rotate) and their spectral properties, and asteroid sizes can be estimated by timing the lengths of star occultations (when an asteroid passes directly in front of a star). [[Radar]] imaging can yield good information about asteroid shapes and orbital and rotational parameters, especially for near-Earth asteroids. In terms of [[delta-v]] and propellant requirements, NEOs are more easily accessible than the Moon. The first close-up photographs of asteroid-like objects were taken in 1971, when the ''[[Mariner 9]]'' probe imaged [[Phobos (moon)|Phobos]] and [[Deimos (moon)|Deimos]], the two small moons of [[Mars]], which are probably captured asteroids. These images revealed the irregular, potato-like shapes of most asteroids, as did later images from the [[Voyager program|Voyager]] probes of the small moons of the [[gas giant]]. The first true asteroid to be photographed in close-up was [[951 Gaspra]] in 1991, followed in 1993 by [[243 Ida]] and its moon [[Dactyl (asteroid)|Dactyl]], all of which were imaged by the [[Galileo (spacecraft)|''Galileo'' probe]] en route to [[Jupiter]]. The first dedicated asteroid probe was ''[[NEAR Shoemaker]]'', which photographed [[253 Mathilde]] in 1997, before entering into orbit around [[433 Eros]], finally landing on its surface in 2001. Other asteroids briefly visited by spacecraft en route to other destinations include [[9969 Braille]] (by ''[[Deep Space 1]]'' in 1999), and [[5535 Annefrank]] (by ''[[Stardust (spacecraft)|Stardust]]'' in 2002). From September to November 2005, the Japanese ''[[Hayabusa (spacecraft)|Hayabusa]]'' probe studied [[25143 Itokawa]] in detail and was plagued with difficulties, but [[Sample return mission|returned samples]] of its surface to Earth on 13 June 2010. The European [[Rosetta (spacecraft)|''Rosetta'' probe]] (launched in 2004) flew by [[2867 Šteins]] in 2008 and [[21 Lutetia]], the third-largest asteroid visited to date, in 2010. In September 2007, [[NASA]] launched the [[Dawn (spacecraft)|''Dawn'' spacecraft]], which orbited [[4 Vesta]] from July 2011 to September 2012, and has been orbiting the dwarf planet [[Ceres (dwarf planet)|1 Ceres]] since 2015. 4 Vesta is the second-largest asteroid visited to date. On 13 December 2012, China's lunar orbiter ''[[Chang'e 2]]'' flew within of the asteroid [[4179 Toutatis]] on an extended mission. The Japan Aerospace Exploration Agency (JAXA) launched the ''[[Hayabusa2]]'' probe in December 2014, and plans to return samples from [[162173 Ryugu]] in December 2020. In June 2018, the US [[National Science and Technology Council]] warned that America is unprepared for an [[Asteroid impact avoidance|asteroid impact event]], and has developed and released the ''"National Near-Earth Object Preparedness Strategy Action Plan"'' to better prepare. | 791 | Asteroid | [
"Asteroids",
"Minor planets"
] | [
"Aten asteroid",
"Centaur (minor planet)",
"Category:Asteroids",
"List of minor planets",
"ʻOumuamua",
"Near Earth Object Surveillance Satellite",
"Category:Asteroid groups and families",
"Apollo asteroid",
"Category:Binary asteroids",
"Amor asteroid",
"Minor planet",
"''Dawn'' (spacecraft)",
"Asteroid impact avoidance",
"Lost minor planet",
"Mesoplanet",
"List of minor planets named after people",
"NEOShield",
"Dwarf planet",
"List of possible impact structures on Earth",
"''Marco Polo'' (spacecraft)",
"List of minor planets named after places",
"Impact event",
"Atira asteroid",
"Chang'e 2 lunar orbiter",
"Constellation program",
"Active asteroid",
"List of impact craters on Earth",
"List of exceptional asteroids",
"''Rosetta'' (spacecraft)",
"Near-Earth object",
"List of asteroid close approaches to Earth",
"Pioneer 10",
"BOOTES",
"Asteroid Day",
"Meanings of minor planet names"
] |
[
"Exploration"
] | In September 2016, NASA launched the [[OSIRIS-REx]] sample return mission to asteroid [[101955 Bennu]], which it reached in December 2018. , the probe is in orbit around the asteroid. | 791 | Asteroid | [
"Asteroids",
"Minor planets"
] | [
"Aten asteroid",
"Centaur (minor planet)",
"Category:Asteroids",
"List of minor planets",
"ʻOumuamua",
"Near Earth Object Surveillance Satellite",
"Category:Asteroid groups and families",
"Apollo asteroid",
"Category:Binary asteroids",
"Amor asteroid",
"Minor planet",
"''Dawn'' (spacecraft)",
"Asteroid impact avoidance",
"Lost minor planet",
"Mesoplanet",
"List of minor planets named after people",
"NEOShield",
"Dwarf planet",
"List of possible impact structures on Earth",
"''Marco Polo'' (spacecraft)",
"List of minor planets named after places",
"Impact event",
"Atira asteroid",
"Chang'e 2 lunar orbiter",
"Constellation program",
"Active asteroid",
"List of impact craters on Earth",
"List of exceptional asteroids",
"''Rosetta'' (spacecraft)",
"Near-Earth object",
"List of asteroid close approaches to Earth",
"Pioneer 10",
"BOOTES",
"Asteroid Day",
"Meanings of minor planet names"
] |
[
"Exploration",
"Planned and future missions"
] | In early 2013, NASA announced the planning stages of a mission to capture a near-Earth asteroid and move it into lunar orbit where it could possibly be visited by astronauts and later impacted into the Moon. On 19 June 2014, NASA reported that asteroid [[2011 MD]] was a prime candidate for capture by a robotic mission, perhaps in the early 2020s. It has been suggested that asteroids might be used as a source of materials that may be rare or exhausted on Earth ([[asteroid mining]]), or materials for constructing [[space habitat]] ''(see [[Colonization of the asteroids]])''. Materials that are heavy and expensive to launch from Earth may someday be mined from asteroids and used for [[space manufacturing]] and construction. In the U.S. [[Discovery program]] the [[Psyche (spacecraft)|''Psyche'' spacecraft]] proposal to [[16 Psyche]] and [[Lucy (spacecraft)|''Lucy'' spacecraft]] to [[Jupiter trojan]] made it to the semi-finalist stage of mission selection. In January 2017, ''Lucy'' and [[Psyche (spacecraft)|''Psyche'' mission]] were both selected as NASA's [[Discovery Program]] missions 13 and 14 respectively. Location of Ceres (within asteroid belt) compared to other bodies of the Solar System | 791 | Asteroid | [
"Asteroids",
"Minor planets"
] | [
"Aten asteroid",
"Centaur (minor planet)",
"Category:Asteroids",
"List of minor planets",
"ʻOumuamua",
"Near Earth Object Surveillance Satellite",
"Category:Asteroid groups and families",
"Apollo asteroid",
"Category:Binary asteroids",
"Amor asteroid",
"Minor planet",
"''Dawn'' (spacecraft)",
"Asteroid impact avoidance",
"Lost minor planet",
"Mesoplanet",
"List of minor planets named after people",
"NEOShield",
"Dwarf planet",
"List of possible impact structures on Earth",
"''Marco Polo'' (spacecraft)",
"List of minor planets named after places",
"Impact event",
"Atira asteroid",
"Chang'e 2 lunar orbiter",
"Constellation program",
"Active asteroid",
"List of impact craters on Earth",
"List of exceptional asteroids",
"''Rosetta'' (spacecraft)",
"Near-Earth object",
"List of asteroid close approaches to Earth",
"Pioneer 10",
"BOOTES",
"Asteroid Day",
"Meanings of minor planet names"
] |
[
"Fiction"
] | Asteroids and the asteroid belt are a staple of science fiction stories. Asteroids play several potential roles in science fiction: as places human beings might colonize, resources for extracting minerals, hazards encountered by spacecraft traveling between two other points, and as a threat to life on Earth or other inhabited planets, dwarf planets, and natural satellites by potential impact. | 791 | Asteroid | [
"Asteroids",
"Minor planets"
] | [
"Aten asteroid",
"Centaur (minor planet)",
"Category:Asteroids",
"List of minor planets",
"ʻOumuamua",
"Near Earth Object Surveillance Satellite",
"Category:Asteroid groups and families",
"Apollo asteroid",
"Category:Binary asteroids",
"Amor asteroid",
"Minor planet",
"''Dawn'' (spacecraft)",
"Asteroid impact avoidance",
"Lost minor planet",
"Mesoplanet",
"List of minor planets named after people",
"NEOShield",
"Dwarf planet",
"List of possible impact structures on Earth",
"''Marco Polo'' (spacecraft)",
"List of minor planets named after places",
"Impact event",
"Atira asteroid",
"Chang'e 2 lunar orbiter",
"Constellation program",
"Active asteroid",
"List of impact craters on Earth",
"List of exceptional asteroids",
"''Rosetta'' (spacecraft)",
"Near-Earth object",
"List of asteroid close approaches to Earth",
"Pioneer 10",
"BOOTES",
"Asteroid Day",
"Meanings of minor planet names"
] |
[] | An '''allocution''', or '''allocutus''', is a formal statement made to the court by the defendant who has been found [[guilt (law)|guilty]] prior to being sentenced. It is part of the criminal procedure in some jurisdictions using [[common law]]. | 794 | Allocution | [
"Criminal procedure",
"Evidence law"
] | [
"Confession (law)"
] |
[
"Concept"
] | An allocution allows the defendant to explain why the sentence should be lenient. In [[plea bargain]], an allocution may be required of the defendant. The defendant explicitly admits specifically and in detail the actions and their reasons in exchange for a reduced sentence. In principle, that removes any doubt as to the exact nature of the defendant's guilt in the matter. The term "allocution" is used generally only in jurisdictions in the United States, but there are vaguely similar processes in other [[common law countries]]. In many other jurisdictions, it is for the defense lawyer to mitigate on his client's behalf, and the defendant rarely has the opportunity to speak. The right of victims to speak at sentencing is also sometimes referred to as allocution. | 794 | Allocution | [
"Criminal procedure",
"Evidence law"
] | [
"Confession (law)"
] |
[
"Australia"
] | In [[Australia]], the term ''allocutus'' is used by the Clerk of Arraigns or another formal associate of the Court. It is generally phrased as, "Prisoner at the Bar, you have been found Guilty by a jury of your peers of the offense of XYZ. Do you have anything to say as to why the sentence of this Court should not now be passed upon you?" The defense counsel will then make a ''plea in mitigation'' (also called ''submissions on penalty'') in an attempt to mitigate the relative seriousness of the offense and heavily refer to and rely upon the defendant's previous good character and good works, if any. The right to make a plea in mitigation is absolute. If a judge or magistrate refuses to hear such a plea or does not properly consider it, the sentence can be overturned on appeal. | 794 | Allocution | [
"Criminal procedure",
"Evidence law"
] | [
"Confession (law)"
] |
[
"United States"
] | In most of the [[United States]], defendants are allowed the opportunity to allocute before a sentence is passed. Some jurisdictions hold that as an absolute right. In its absence, a sentence but not the conviction may be overturned, resulting in the need for a new sentencing hearing. In the federal system, [[Federal Rules of Criminal Procedure]] 32(i)(4) provides that the court must "address the defendant personally in order to permit the defendant to speak or present any information to mitigate the sentence." The [[Federal Public Defender]] recommends that defendants speak in terms of how a lenient sentence will be sufficient but not greater than necessary to comply with the statutory directives set forth in . | 794 | Allocution | [
"Criminal procedure",
"Evidence law"
] | [
"Confession (law)"
] |
[] | An '''''' ( ; [[Medieval Latin]] for ''he has declared under oath'') is a written statement of fact voluntarily made by an ''affiant'' or ''[[Deposition (law)|deponent]]'' under an [[oath]] or affirmation which is administered by a person who is authorized to do so by law. Such a statement is witnessed as to the authenticity of the affiant's [[signature]] by a taker of oaths, such as a [[notary public]] or commissioner of oaths. An affidavit is a type of verified statement or showing, or in other words, it contains a verification, which means that it is made under oath on penalty of [[perjury]], and this serves as evidence for its veracity and is required in court proceedings. Affidavits may be written in the first or third person, depending on who drafted the document. The document's component parts are typically as follows: (-) a ''commencement'' which identifies the "affiant of truth", generally stating that everything in it is true, under penalty of perjury, fine, or imprisonment; (-) an ''attestation'' clause, usually a [[jurat (clause)|jurat]], at the end certifying that the affiant made oath and the date; (-) signatures of the author and witness. If an affidavit is notarized or authenticated, it will also include a caption with a venue and title in reference to judicial proceedings. In some cases, an introductory clause, called a ''preamble'', is added attesting that the affiant personally appeared before the authenticating authority. | 795 | Affidavit | [
"Evidence law",
"Legal documents",
"Notary"
] | [
"Fishman Affidavit",
"Statutory declaration",
"Performativity",
"Declaration (law)",
"Deposition (law)",
"Sworn declaration"
] |
[
"Australia"
] | On 2 March 2016, the High Court of Australia held that the ACT Uniform Evidence Legislation is neutral in the way sworn evidence and unsworn evidence is treated as being of equal weight. | 795 | Affidavit | [
"Evidence law",
"Legal documents",
"Notary"
] | [
"Fishman Affidavit",
"Statutory declaration",
"Performativity",
"Declaration (law)",
"Deposition (law)",
"Sworn declaration"
] |
[
"India"
] | In Indian law, although an affidavit may be taken as proof of the facts stated therein, the courts have no jurisdiction to admit evidence by way of affidavit. Affidavit is not treated as "evidence" within the meaning of Section 3 of the Evidence Act. However, it was held by the Supreme Court that an affidavit can be used as evidence only if the court so orders for sufficient reasons, namely, the right of the opposite party to have the deponent produced for cross-examination. Therefore, an affidavit cannot ordinarily be used as evidence in absence of a specific order of the court. | 795 | Affidavit | [
"Evidence law",
"Legal documents",
"Notary"
] | [
"Fishman Affidavit",
"Statutory declaration",
"Performativity",
"Declaration (law)",
"Deposition (law)",
"Sworn declaration"
] |
[
"Sri Lanka"
] | In Sri Lanka, under the Oaths Ordinance, with the exception of a [[court-martial]], a person may submit an affidavit signed in the presence of a [[commissioner for oaths]] or a [[Justice of the peace#Sri Lanka|justice of the peace]]. | 795 | Affidavit | [
"Evidence law",
"Legal documents",
"Notary"
] | [
"Fishman Affidavit",
"Statutory declaration",
"Performativity",
"Declaration (law)",
"Deposition (law)",
"Sworn declaration"
] |
[
"Ireland"
] | Affidavits are made in a similar way as to England and Wales, although "make oath" is sometimes omitted. A declaration may be substituted for an affidavit in most cases for those opposed to swearing oaths. The person making the affidavit is known as the deponent but does not sign the affidavit. The affidavit concludes in the standard format "sworn (declared) before me, [name of commissioner for oaths/solicitor], a commissioner for oaths (solicitor), on the [date] at [location] in the county/city of [county/city], and I know the deponent (declarant)", and it is signed and stamped by the commissioner for oaths. In August 2020 a new method of filing affidavits came into force. Under Section 21 of the Civil Law and Criminal Law (Miscellaneous Provisions) Act 2020 witnesses are no longer required to swear before God or make an affirmation when filing an affidavit. Instead, witnesses will make a non-religious “statement of truth” and will be liable for up to one year in prison if it is breached. | 795 | Affidavit | [
"Evidence law",
"Legal documents",
"Notary"
] | [
"Fishman Affidavit",
"Statutory declaration",
"Performativity",
"Declaration (law)",
"Deposition (law)",
"Sworn declaration"
] |
[
"United States"
] | In American [[jurisprudence]], under the rules for [[Hearsay in United States law|hearsay]], admission of an unsupported affidavit as evidence is unusual (especially if the affiant is not available for [[cross-examination]]) with regard to material facts which may be dispositive of the matter at bar. Affidavits from persons who are dead or otherwise incapacitated, or who cannot be located or made to appear, may be accepted by the court, but usually only in the presence of [[corroborating evidence]]. An affidavit which reflected a better grasp of the facts close in time to the actual events may be used to refresh a witness's recollection. Materials used to refresh recollection are admissible as evidence. If the affiant is a party in the case, the affiant's opponent may be successful in having the affidavit admitted as evidence, as statements by a party-opponent are admissible through an exception to the hearsay rule. Affidavits are typically included in the response to [[interrogatories]]. [[Requests for admissions]] under Federal Rule of Civil Procedure 36, however, are not required to be sworn. When a person signs an affidavit, that person is eligible to take the stand at a trial or evidentiary hearing. One party may wish to summon the affiant to verify the contents of the affidavit, while the other party may want to cross-examine the affiant about the affidavit. Some types of motions will not be accepted by the court unless accompanied by an independent sworn statement or other evidence in support of the need for the motion. In such a case, a court will accept an affidavit from the filing attorney in support of the motion, as certain assumptions are made, to wit: The affidavit in place of sworn testimony promotes [[judicial economy]]. The lawyer is an [[officer of the court]] and knows that a false swearing by them, if found out, could be grounds for severe penalty up to and including [[disbarment]]. The lawyer if called upon would be able to present independent and more detailed evidence to prove the facts set forth in his affidavit. The acceptance of an affidavit by one society does not confirm its acceptance as a legal document in other jurisdictions. Equally, the acceptance that a lawyer is an officer of the court (for swearing the affidavit) is not a given. This matter is addressed by the use of the apostille, a means of certifying the legalization of a document for international use under the terms of the [[Apostille Convention|1961 Hague Convention Abolishing the Requirement of Legalization for Foreign Public Documents]]. Documents which have been notarized by a notary public, and certain other documents, and then certified with a conformant apostille, are accepted for legal use in all the nations that have signed the Hague Convention. Thus most affidavits now require to be apostilled if used for cross border issues. | 795 | Affidavit | [
"Evidence law",
"Legal documents",
"Notary"
] | [
"Fishman Affidavit",
"Statutory declaration",
"Performativity",
"Declaration (law)",
"Deposition (law)",
"Sworn declaration"
] |
[
"Types of affidavit"
] | There are a various circumstances when a person may need an particular type of affidavit for a specific purpose such as the following: (-) Affidavit of Citizenship (-) Affidavit of Death (-) Affidavit of Heirship (-) Affidavit of Identity Theft (-) Affidavit of Name Change (-) Affidavit of Residence (-) Affidavit of Service (-) Affidavit of Small Estate (-) Affidavit of Support (-) Divorce Affidavit (-) Financial Affidavit | 795 | Affidavit | [
"Evidence law",
"Legal documents",
"Notary"
] | [
"Fishman Affidavit",
"Statutory declaration",
"Performativity",
"Declaration (law)",
"Deposition (law)",
"Sworn declaration"
] |
[] | '''Aries ''' is one of the [[constellation]] of the [[zodiac]]. It is located in the [[Northern celestial hemisphere]] between [[Pisces (constellation)|Pisces]] to the west and [[Taurus (constellation)|Taurus]] to the east. The name Aries is [[Latin]] for [[sheep|ram]], and its symbol is (Unicode ♈), representing a ram's horns. It is one of the 48 constellations described by the 2nd century astronomer [[Ptolemy]], and remains one of the 88 modern constellations. It is a mid-sized constellation, ranking 39th overall size, with an area of 441 square degrees (1.1% of the [[celestial sphere]]). Aries has represented a ram since late Babylonian times. Before that, the stars of Aries formed a farmhand. Different cultures have incorporated the stars of Aries into different constellations including twin inspectors in China and a porpoise in the Marshall Islands. Aries is a relatively dim constellation, possessing only four bright stars: [[Hamal]] (Alpha Arietis, second magnitude), [[Sheratan]] (Beta Arietis, third magnitude), [[Mesarthim]] (Gamma Arietis, fourth magnitude), and [[41 Arietis]] (also fourth magnitude). The few [[deep-sky object]] within the constellation are quite faint and include several pairs of interacting galaxies. Several [[meteor shower]] appear to radiate from Aries, including the [[Daytime Arietids]] and the [[Epsilon Arietids]]. | 798 | Aries (constellation) | [
"Aries (constellation)",
"Constellations",
"Constellations listed by Ptolemy",
"Northern constellations"
] | [] |
[
"History and mythology"
] | Aries is recognized as an official constellation now, albeit as a specific region of the sky, by the [[International Astronomical Union]]. It was originally defined in ancient texts as a specific pattern of stars, and has remained a constellation since ancient times; it now includes the ancient pattern as well as the surrounding stars. In the description of the [[Babylonian zodiac]] given in the clay tablets known as the [[MUL.APIN]], the constellation, now known as Aries, was the final station along the [[ecliptic]]. The MUL.APIN was a comprehensive table of the risings and settings of stars, which likely served as an agricultural calendar. Modern-day Aries was known as , "The Agrarian Worker" or "The Hired Man". Although likely compiled in the 12th or 11th century BC, the MUL.APIN reflects a tradition which marks the [[Pleiades]] as the [[Vernal equinox (Northern Hemisphere)|vernal equinox]], which was the case with some precision at the beginning of the [[Middle Bronze Age]]. The earliest identifiable reference to Aries as a distinct constellation comes from the [[boundary stone]] that date from 1350 to 1000 BC. On several boundary stones, a zodiacal ram figure is distinct from the other characters present. The shift in identification from the constellation as the Agrarian Worker to the Ram likely occurred in later Babylonian tradition because of its growing association with [[Dumuzi the Shepherd]]. By the time the MUL.APIN was created—by 1000 BC—modern Aries was identified with both Dumuzi's ram and a hired laborer. The exact timing of this shift is difficult to determine due to the lack of images of Aries or other ram figures. In [[ancient Egyptian astronomy]], Aries was associated with the god [[Amon-Ra]], who was depicted as a man with a ram's head and represented fertility and creativity. Because it was the location of the vernal equinox, it was called the "Indicator of the Reborn Sun". During the times of the year when Aries was prominent, priests would process statues of Amon-Ra to temples, a practice that was modified by [[Persian astronomy|Persian astronomers]] centuries later. Aries acquired the title of "Lord of the Head" in Egypt, referring to its symbolic and mythological importance. Aries was not fully accepted as a constellation until classical times. In [[Hellenistic astrology]], the constellation of Aries is associated with the golden ram of [[Greek mythology]] that rescued [[Phrixus]] and [[Helle (mythology)|Helle]] on orders from [[Hermes]], taking Phrixus to the land of [[Colchis]]. Phrixos and Helle were the son and daughter of King [[Athamas]] and his first wife [[Nephele]]. The king's second wife, [[Ino (Greek mythology)|Ino]], was jealous and wished to kill his children. To accomplish this, she induced a famine in [[Boeotia]], then falsified a message from the [[Oracle of Delphi]] that said Phrixos must be sacrificed to end the famine. Athamas was about to sacrifice his son atop [[Mount Laphystium]] when Aries, sent by Nephele, arrived. Helle fell off of Aries's back in flight and drowned in the [[Dardanelles]], also called the Hellespont in her honor. | 798 | Aries (constellation) | [
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"Northern constellations"
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[
"History and mythology"
] | Historically, Aries has been depicted as a crouched, wingless ram with its head turned towards Taurus. [[Ptolemy]] asserted in his ''[[Almagest]]'' that [[Hipparchus]] depicted [[Alpha Arietis]] as the ram's muzzle, though Ptolemy did not include it in his constellation figure. Instead, it was listed as an "unformed star", and denoted as "the star over the head". [[John Flamsteed]], in his ''[[Atlas Coelestis]]'', followed Ptolemy's description by mapping it above the figure's head. Flamsteed followed the general convention of maps by depicting Aries lying down. Astrologically, Aries has been associated with the head and its [[humorism|humors]]. It was strongly associated with [[Mars]], both the planet and the god. It was considered to govern Western Europe and Syria, and to indicate a strong temper in a person. The [[First Point of Aries]], the location of the [[Vernal equinox (Northern Hemisphere)|vernal equinox]], is named for the constellation. This is because the Sun crossed the [[celestial equator]] from south to north in Aries more than two millennia ago. Hipparchus defined it in 130 BC. as a point south of [[Gamma Arietis]]. Because of the [[precession of the equinoxes]], the First Point of Aries has since moved into [[Pisces (constellation)|Pisces]] and will move into [[Aquarius (constellation)|Aquarius]] by around 2600 AD. The Sun now appears in Aries from late April through mid May, though the constellation is still associated with the beginning of spring. [[Islamic astronomy|Medieval Muslim astronomers]] depicted Aries in various ways. Astronomers like [[al-Sufi]] saw the constellation as a ram, modeled on the precedent of Ptolemy. However, some Islamic celestial globes depicted Aries as a nondescript four-legged animal with what may be antlers instead of horns. Some early [[Bedouin]] observers saw a ram elsewhere in the sky; this constellation featured the [[Pleiades]] as the ram's tail. The generally accepted Arabic formation of Aries consisted of thirteen stars in a figure along with five "unformed" stars, four of which were over the animal's hindquarters and one of which was the disputed star over Aries's head. Al-Sufi's depiction differed from both other Arab astronomers' and Flamsteed's, in that his Aries was running and looking behind itself. The [[obsolete constellations]] of Aries ([[Apes (constellation)|Apes]]/[[Vespa (constellation)|Vespa]]/[[Lilium (constellation)|Lilium]]/[[Musca Borealis|Musca (Borealis)]]) all centred on the same the northern stars. In 1612, [[Petrus Plancius]] introduced Apes, a constellation representing a bee. In 1624, the same stars were used by [[Jakob Bartsch]] as for Vespa, representing a wasp. In 1679 [[Augustin Royer]] used these stars for his constellation Lilium, representing the [[fleur-de-lis]]. None of these constellation became widely accepted. [[Johann Hevelius]] renamed the constellation "Musca" in 1690 in his ''[[Firmamentum Sobiescianum]]''. To differentiate it from [[Musca]], the southern fly, it was later renamed Musca Borealis but it did not gain acceptance and its stars were ultimately officially reabsorbed into Aries. The asterism involved was [[33 Arietis|33]], [[35 Arietis|35]], [[39 Arietis|39]], and [[41 Arietis]]. | 798 | Aries (constellation) | [
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[
"History and mythology"
] | In 1922, the International Astronomical Union defined its recommended three-letter abbreviation, "Ari". The official boundaries of Aries were defined in 1930 by [[Eugène Delporte]] as a polygon of 12 segments. Its [[right ascension]] is between 1 46.4 and 3 29.4 and its [[declination]] is between 10.36° and 31.22° in the [[equatorial coordinate system]]. | 798 | Aries (constellation) | [
"Aries (constellation)",
"Constellations",
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[
"History and mythology",
"In non-Western astronomy"
] | In traditional [[Chinese astronomy]], stars from Aries were used in several constellations. The brightest stars—Alpha, Beta, and Gamma Arietis—formed a constellation called ''Lou'' (婁), variously translated as "bond", "lasso", and "sickle", which was associated with the ritual sacrifice of cattle. This name was shared by the [[Twenty-eight mansions|16th lunar mansion]], the location of the full moon closest to the [[September equinox|autumnal equinox]]. This constellation has also been associated with harvest-time as it could represent a woman carrying a basket of food on her head. [[35 Arietis|35]], [[39 Arietis|39]], and [[41 Arietis]] were part of a constellation called ''Wei'' (胃), which represented a fat abdomen and was the namesake of the 17th lunar mansion, which represented [[granary|granaries]]. [[Delta Arietis|Delta]] and [[Zeta Arietis]] were a part of the constellation ''Tianyin'' (天陰), thought to represent the Emperor's hunting partner. ''Zuogeng'' (左更), a constellation depicting a marsh and pond inspector, was composed of [[Mu Arietis|Mu]], [[Nu Arietis|Nu]], [[Omicron Arietis|Omicron]], [[Pi Arietis|Pi]], and [[Sigma Arietis]]. He was accompanied by ''Yeou-kang'', a constellation depicting an official in charge of pasture distribution. In a similar system to the Chinese, the first lunar mansion in [[Hindu astronomy]] was called "Aswini", after the traditional names for Beta and Gamma Arietis, the [[Ashvins|Aswins]]. Because the Hindu new year began with the vernal equinox, the [[Rig Veda]] contains over 50 new-year's related hymns to the twins, making them some of the most prominent characters in the work. Aries itself was known as "''Aja''" and "''Mesha''". In [[Hebrew astronomy]] Aries was named "''Taleh''"; it signified either [[Tribe of Simeon|Simeon]] or [[Tribe of Gad|Gad]], and generally symbolizes the "Lamb of the World". The neighboring [[Syria]] named the constellation "Amru", and the bordering Turks named it "Kuzi". Half a world away, in the [[Marshall Islands]], several stars from Aries were incorporated into a constellation depicting a [[porpoise]], along with stars from [[Cassiopeia (constellation)|Cassiopeia]], [[Andromeda (constellation)|Andromeda]], and [[Triangulum]]. Alpha, Beta, and Gamma Arietis formed the head of the porpoise, while stars from Andromeda formed the body and the bright stars of Cassiopeia formed the tail. Other [[Polynesian people]] recognized Aries as a constellation. The [[Marquesas]] islanders called it ''Na-pai-ka''; the [[Māori people|Māori]] constellation ''Pipiri'' may correspond to modern Aries as well. In indigenous Peruvian astronomy, a constellation with most of the same stars as Aries existed. It was called the "Market Moon" and the "Kneeling Terrace", as a reminder for when to hold the annual harvest festival, [[Ayri Huay]]. | 798 | Aries (constellation) | [
"Aries (constellation)",
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[
"Features",
"Stars"
] | Aries has three prominent stars forming an [[Asterism (astronomy)|asterism]], designated Alpha, Beta, and Gamma Arietis by [[Johann Bayer]]. Alpha (Hamal) and Beta (Sheratan) are commonly used for navigation. There is also one other star above the fourth magnitude, 41 Arietis (Bharani). [[Alpha Arietis|α Arietis]], called Hamal, is the brightest [[star]] in Aries. Its traditional name is derived from the Arabic word for "lamb" or "head of the ram" (''ras al-hamal''), which references Aries's mythological background. With a [[spectral class]] of K2 and a [[luminosity class]] of III, it is an [[orange giant]] with an [[apparent visual magnitude]] of 2.00, which lies 66 [[light-year]] from Earth. Hamal has a [[luminosity]] of and its [[absolute magnitude]] is −0.1. [[Beta Arietis|β Arietis]], also known as Sheratan, is a blue-white star with an apparent visual magnitude of 2.64. Its traditional name is derived from "''sharatayn''", the Arabic word for "the two signs", referring to both Beta and Gamma Arietis in their position as heralds of the vernal equinox. The two stars were known to the [[Bedouin]] as "''qarna al-hamal''", "horns of the ram". It is 59 light-years from Earth. It has a luminosity of and its absolute magnitude is 2.1. It is a [[spectroscopic binary]] star, one in which the companion star is only known through [[spectroscopy|analysis of the spectra]]. The spectral class of the primary is A5. [[Hermann Carl Vogel]] determined that Sheratan was a spectroscopic binary in 1903; its orbit was determined by [[Hans Ludendorff]] in 1907. It has since been studied for its eccentric orbit. [[Gamma Arietis|γ Arietis]], with a common name of Mesarthim, is a [[binary star]] with two white-hued components, located in a rich field of magnitude 8–12 stars. Its traditional name has conflicting derivations. It may be derived from a corruption of "al-sharatan", the Arabic word meaning "pair" or a word for "fat ram". However, it may also come from the Sanskrit for "first star of Aries" or the Hebrew for "ministerial servants", both of which are unusual languages of origin for star names. Along with Beta Arietis, it was known to the Bedouin as "''qarna al-hamal''". The primary is of magnitude 4.59 and the secondary is of magnitude 4.68. The system is 164 light-years from Earth. The two components are separated by 7.8 [[arcsecond]], and the system as a whole has an [[apparent magnitude]] of 3.9. The primary has a luminosity of and the secondary has a luminosity of ; the primary is an A-type star with an absolute magnitude of 0.2 and the secondary is a B9-type star with an absolute magnitude of 0.4. The angle between the two components is 1°. Mesarthim was discovered to be a double star by [[Robert Hooke]] in 1664, one of the earliest such telescopic discoveries. The primary, γ Arietis, is an [[Alpha² Canum Venaticorum variable]] star that has a range of 0.02 magnitudes and a period of 2.607 days. It is unusual because of its strong [[silicon]] [[emission lines]]. | 798 | Aries (constellation) | [
"Aries (constellation)",
"Constellations",
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[
"Features",
"Stars"
] | The constellation is home to several double stars, including Epsilon, Lambda, and Pi Arietis. [[Epsilon Arietis|ε Arietis]] is a binary star with two white components. The primary is of magnitude 5.2 and the secondary is of magnitude 5.5. The system is 290 light-years from Earth. Its overall magnitude is 4.63, and the primary has an absolute magnitude of 1.4. Its spectral class is A2. The two components are separated by 1.5 arcseconds. [[Lambda Arietis|λ Arietis]] is a wide double star with a white-hued primary and a yellow-hued secondary. The primary is of magnitude 4.8 and the secondary is of magnitude 7.3. The primary is 129 light-years from Earth. It has an absolute magnitude of 1.7 and a spectral class of F0. The two components are separated by 36 arcseconds at an angle of 50°; the two stars are located 0.5° east of [[7 Arietis]]. [[Pi Arietis|π Arietis]] is a close binary star with a blue-white primary and a white secondary. The primary is of magnitude 5.3 and the secondary is of magnitude 8.5. The primary is 776 light-years from Earth. The primary itself is a wide double star with a separation of 25.2 arcseconds; the tertiary has a magnitude of 10.8. The primary and secondary are separated by 3.2 arcseconds. Most of the other stars in Aries visible to the naked eye have magnitudes between 3 and 5. [[Delta Arietis|δ Ari]], called Boteïn, is a star of magnitude 4.35, 170 light-years away. It has an absolute magnitude of −0.1 and a spectral class of K2. [[Zeta Arietis|ζ Arietis]] is a star of magnitude 4.89, 263 light-years away. Its spectral class is A0 and its absolute magnitude is 0.0. [[14 Arietis]] is a star of magnitude 4.98, 288 light-years away. Its spectral class is F2 and its absolute magnitude is 0.6. [[39 Arietis]] (Lilii Borea) is a similar star of magnitude 4.51, 172 light-years away. Its spectral class is K1 and its absolute magnitude is 0.0. [[35 Arietis]] is a dim star of magnitude 4.55, 343 light-years away. Its spectral class is B3 and its absolute magnitude is −1.7. [[41 Arietis]], known both as c Arietis and Nair al Butain, is a brighter star of magnitude 3.63, 165 light-years away. Its spectral class is B8 and it has a luminosity of . Its absolute magnitude is −0.2. [[53 Arietis]] is a [[runaway star]] of magnitude 6.09, 815 light-years away. Its spectral class is B2. It was likely ejected from the [[Orion Nebula]] approximately five million years ago, possibly due to [[supernova]]. Finally, [[Teegarden's Star]] is the closest star to Earth in Aries. It is a [[brown dwarf]] of magnitude 15.14 and spectral class M6.5V. With a proper motion of 5.1 arcseconds per year, it is the 24th closest star to Earth overall. | 798 | Aries (constellation) | [
"Aries (constellation)",
"Constellations",
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[
"Features",
"Stars"
] | Aries has its share of variable stars, including R and U Arietis, Mira-type variable stars, and T Arietis, a semi-regular variable star. [[R Arietis]] is a [[Mira variable]] star that ranges in magnitude from a minimum of 13.7 to a maximum of 7.4 with a period of 186.8 days. It is 4,080 light-years away. [[U Arietis]] is another Mira variable star that ranges in magnitude from a minimum of 15.2 to a maximum of 7.2 with a period of 371.1 days. [[T Arietis]] is a [[semiregular variable star]] that ranges in magnitude from a minimum of 11.3 to a maximum of 7.5 with a period of 317 days. It is 1,630 light-years away. One particularly interesting variable in Aries is [[SX Arietis]], a rotating variable star considered to be the prototype of its class, [[helium variable]] stars. SX Arietis stars have very prominent emission lines of Helium I and Silicon III. They are normally main-sequence B0p—B9p stars, and their variations are not usually visible to the naked eye. Therefore, they are observed photometrically, usually having periods that fit in the course of one night. Similar to [[Alpha² Canum Venaticorum variable]], SX Arietis stars have periodic changes in their light and magnetic field, which correspond to the periodic rotation; they differ from the Alpha² Canum Venaticorum variables in their higher temperature. There are between 39 and 49 SX Arietis variable stars currently known; ten are noted as being "uncertain" in the [[General Catalog of Variable Stars]]. | 798 | Aries (constellation) | [
"Aries (constellation)",
"Constellations",
"Constellations listed by Ptolemy",
"Northern constellations"
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[
"Features",
"Deep-sky objects"
] | [[NGC 772]] is a [[spiral galaxy]] with an [[integrated magnitude]] of 10.3, located southeast of β Arietis and 15 arcminutes west of [[15 Arietis]]. It is a relatively bright galaxy and shows obvious nebulosity and ellipticity in an amateur telescope. It is 7.2 by 4.2 arcminutes, meaning that its [[surface brightness]], magnitude 13.6, is significantly lower than its integrated magnitude. NGC 772 is a [[galaxy morphological classification|class SA(s)b galaxy]], which means that it is an unbarred spiral galaxy without a ring that possesses a somewhat prominent [[bulge (astronomy)|bulge]] and spiral arms that are wound somewhat tightly. The main arm, on the northwest side of the galaxy, is home to many [[star formation|star forming regions]]; this is due to previous [[galaxy merger|gravitational interactions]] with other galaxies. NGC 772 has a small companion galaxy, [[NGC 770]], that is about 113,000 light-years away from the larger galaxy. The two galaxies together are also classified as Arp 78 in the [[Arp number|Arp peculiar galaxy catalog]]. NGC 772 has a diameter of 240,000 light-years and the system is 114 million light-years from Earth. Another spiral galaxy in Aries is [[NGC 673]], a face-on class SAB(s)c galaxy. It is a weakly [[barred spiral galaxy]] with loosely wound arms. It has no ring and a faint bulge and is 2.5 by 1.9 arcminutes. It has two primary arms with fragments located farther from the core. 171,000 light-years in diameter, NGC 673 is 235 million light-years from Earth. [[NGC 678]] and [[NGC 680]] are a pair of galaxies in Aries that are only about 200,000 light-years apart. Part of the [[NGC 691]] group of galaxies, both are at a distance of approximately 130 million light-years. NGC 678 is an edge-on spiral galaxy that is 4.5 by 0.8 arcminutes. NGC 680, an [[elliptical galaxy]] with an asymmetrical boundary, is the brighter of the two at magnitude 12.9; NGC 678 has a magnitude of 13.35. Both galaxies have bright cores, but NGC 678 is the larger galaxy at a diameter of 171,000 light-years; NGC 680 has a diameter of 72,000 light-years. NGC 678 is further distinguished by its prominent [[dust lane]]. NGC 691 itself is a spiral galaxy slightly inclined to our line of sight. It has multiple spiral arms and a bright core. Because it is so diffuse, it has a low surface brightness. It has a diameter of 126,000 light-years and is 124 million light-years away. [[NGC 877]] is the brightest member of an 8-galaxy group that also includes NGC 870, NGC 871, and NGC 876, with a magnitude of 12.53. It is 2.4 by 1.8 arcminutes and is 178 million light-years away with a diameter of 124,000 light-years. Its companion is NGC 876, which is about 103,000 light-years from the core of NGC 877. They are interacting gravitationally, as they are connected by a faint stream of gas and dust. [[Arp 276]] is a different pair of interacting galaxies in Aries, consisting of NGC 935 and IC 1801. | 798 | Aries (constellation) | [
"Aries (constellation)",
"Constellations",
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[
"Features",
"Deep-sky objects"
] | NGC 821 is an E6 elliptical galaxy. It is unusual because it has hints of an early spiral structure, which is normally only found in [[lenticular galaxy|lenticular]] and spiral galaxies. NGC 821 is 2.6 by 2.0 arcminutes and has a visual magnitude of 11.3. Its diameter is 61,000 light-years and it is 80 million light-years away. Another unusual galaxy in Aries is [[Segue 2 (dwarf galaxy)|Segue 2]], a [[dwarf galaxy|dwarf]] and [[List of Milky Way's satellite galaxies|satellite galaxy of the Milky Way]], recently discovered to be a potential relic of the [[epoch of reionization]]. | 798 | Aries (constellation) | [
"Aries (constellation)",
"Constellations",
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"Northern constellations"
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[
"Features",
"Meteor showers"
] | Aries is home to several [[meteor shower]]. The [[Daytime Arietid]] meteor shower is one of the strongest meteor showers that occurs during the day, lasting from 22 May to 2 July. It is an annual shower associated with the Marsden group of [[comet]] that peaks on 7 June with a maximum [[zenithal hourly rate]] of 54 meteors. Its parent body may be the asteroid [[1566 Icarus|Icarus]]. The meteors are sometimes visible before dawn, because the [[radiant (meteor shower)|radiant]] is 32 degrees away from the Sun. They usually appear at a rate of 1–2 per hour as "earthgrazers", meteors that last several seconds and often begin at the horizon. Because most of the Daytime Arietids are not visible to the naked eye, they are observed in the [[radio spectrum]]. This is possible because of the ionized gas they leave in their wake. Other meteor showers radiate from Aries during the day; these include the Daytime Epsilon Arietids and the Northern and Southern Daytime May Arietids. The [[Jodrell Bank Observatory]] discovered the Daytime Arietids in 1947 when James Hey and G. S. Stewart adapted the [[Battle of Britain#Control systems|World War II-era radar systems]] for meteor observations. The [[Delta Arietids]] are another meteor shower radiating from Aries. Peaking on 9 December with a low peak rate, the shower lasts from 8 December to 14 January, with the highest rates visible from 8 to 14 December. The average Delta Aquarid meteor is very slow, with an average velocity of per second. However, this shower sometimes produces bright [[Fireball (meteor)|fireball]]. This meteor shower has northern and southern components, both of which are likely associated with [[1990 HA]], a [[near-Earth asteroid]]. The [[Autumn Arietids]] also radiate from Aries. The shower lasts from 7 September to 27 October and peaks on 9 October. Its peak rate is low. The [[Epsilon Arietids]] appear from 12 to 23 October. Other meteor showers radiating from Aries include the October Delta Arietids, [[Daytime Epsilon Arietids]], [[Daytime May Arietids]], [[Sigma Arietids]], [[Nu Arietids]], and [[Beta Arietids]]. The Sigma Arietids, a class IV meteor shower, are visible from 12 to 19 October, with a maximum zenithal hourly rate of less than two meteors per hour on 19 October. | 798 | Aries (constellation) | [
"Aries (constellation)",
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[
"Features",
"Planetary systems"
] | Aries contains several stars with [[extrasolar planets]]. [[HIP 14810]], a G5 type star, is orbited by three [[giant planet]] (those more than ten times the [[mass of Earth]]). [[HD 12661]], like HIP 14810, is a G-type main sequence star, slightly larger than the Sun, with two orbiting planets. One planet is 2.3 times the mass of Jupiter, and the other is 1.57 times the mass of Jupiter. [[HD 20367]] is a G0 type star, approximately the size of the Sun, with one orbiting planet. The planet, discovered in 2002, has a mass 1.07 times that of Jupiter and orbits every 500 days. In 2019, scientists conducting the CARMENES survey at the [[Calar Alto Observatory]] announced evidence of two [[Earth analog|Earth-mass exoplanets]] orbiting the star within its [[Circumstellar habitable zone|habitable zone]]. | 798 | Aries (constellation) | [
"Aries (constellation)",
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[] | '''Aquarius''' is a [[constellation]] of the [[zodiac]], between [[Capricornus]] and [[Pisces (constellation)|Pisces]]. Its name is [[Latin]] for "water-carrier" or "cup-carrier", and its symbol is [[Image:Aquarius.svg|20px]] (Unicode ♒), a representation of water. Aquarius is one of the oldest of the recognized constellations along the [[zodiac]] (the [[Sun]]'s apparent path). It was one of the 48 constellations listed by the 2nd century astronomer [[Ptolemy]], and it remains one of the 88 modern constellations. It is found in a region often called the [[Sea (astronomy)|Sea]] due to its profusion of constellations with watery associations such as [[Cetus]] the [[whale]], [[Pisces (constellation)|Pisces]] the [[fish]], and [[Eridanus (constellation)|Eridanus]] the [[river]]. At [[apparent magnitude]] 2.9, [[Beta Aquarii]] is the brightest star in the constellation. | 799 | Aquarius (constellation) | [
"Aquarius (constellation)",
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[
"History and mythology"
] | Aquarius is identified as "The Great One" in the [[Babylonian star catalogues]] and represents the god [[Ea (god)|Ea]] himself, who is commonly depicted holding an overflowing vase. The Babylonian star-figure appears on entitlement stones and [[cylinder seals]] from the [[2nd millennium BC|second millennium]]. It contained the [[winter solstice]] in the Early Bronze Age. In [[Old Babylonian astronomy]], Ea was the ruler of the southernmost quarter of the Sun's path, the "Way of Ea", corresponding to the period of 45 days on either side of winter solstice. Aquarius was also associated with the destructive floods that the Babylonians regularly experienced, and thus was negatively connoted. In [[Egyptian astronomy#Ancient Egypt|Ancient Egypt astronomy]], Aquarius was associated with the annual [[flood of the Nile]]; the banks were said to flood when Aquarius put his jar into the river, beginning spring. In the [[Ancient Greek astronomy|Greek tradition]], the constellation came to be represented simply as a single vase from which a stream poured down to [[Piscis Austrinus]]. The name in the [[Hindu zodiac]] is likewise ''kumbha'' "water-pitcher". In Greek mythology, Aquarius is sometimes associated with [[Deucalion]], the son of [[Prometheus]] who built a ship with his wife [[Pyrrha]] to survive an imminent flood. They sailed for nine days before washing ashore on [[Mount Parnassus]]. Aquarius is also sometimes identified with beautiful [[Ganymede (mythology)|Ganymede]], a youth in [[Greek mythology]] and the son of [[Troy|Trojan]] king [[Tros (mythology)|Tros]], who was taken to [[Mount Olympus]] by [[Zeus]] to act as cup-carrier to the [[Greek pantheon|gods]]. Neighboring [[Aquila (constellation)|Aquila]] represents the eagle, under Zeus' command, that snatched the young boy; some versions of the myth indicate that the eagle was in fact Zeus transformed. An alternative version of the tale recounts Ganymede's kidnapping by the goddess of the dawn, [[Eos]], motivated by her affection for young men; Zeus then stole him from Eos and employed him as cup-bearer. Yet another figure associated with the water bearer is [[Cecrops I]], a king of [[Athens]] who [[sacrifice]] water instead of [[wine]] to the gods. | 799 | Aquarius (constellation) | [
"Aquarius (constellation)",
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[
"History and mythology",
"Depictions"
] | In the first century, [[Ptolemy]]'s ''[[Almagest]]'' established the common Western depiction of Aquarius. His water jar, an asterism itself, consists of Gamma, Pi, Eta, and [[Zeta Aquarii]]; it pours water in a stream of more than 20 stars terminating with [[Fomalhaut]], now assigned solely to [[Piscis Austrinus]]. The water bearer's head is represented by 5th magnitude [[25 Aquarii]] while his left shoulder is [[Beta Aquarii]]; his right shoulder and forearm are represented by [[Alpha Aquarii|Alpha]] and [[Gamma Aquarii]] respectively. | 799 | Aquarius (constellation) | [
"Aquarius (constellation)",
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[
"History and mythology",
"In Eastern astronomy"
] | In [[Chinese astronomy]], the stream of water flowing from the Water Jar was depicted as the "Army of Yu-Lin" (''Yu-lim-kiun'' or ''Yulinjun'', [[Hanzi]]: 羽林君). The name "Yu-lin" means "feathers and forests", referring to the numerous light-footed soldiers from the northern reaches of the empire represented by these faint stars. The constellation's stars were the most numerous of any Chinese constellation, numbering 45, the majority of which were located in modern Aquarius. The celestial army was protected by the wall ''Leibizhen'' (垒壁阵), which counted Iota, Lambda, Phi, and Sigma Aquarii among its 12 stars. 88, 89, and 98 Aquarii represent ''Fou-youe'', the axes used as weapons and for hostage executions. Also in Aquarius is ''Loui-pi-tchin'', the ramparts that stretch from 29 and 27 Piscium and 33 and 30 Aquarii through Phi, Lambda, Sigma, and Iota Aquarii to Delta, Gamma, Kappa, and Epsilon Capricorni. Near the border with [[Cetus]], the axe ''Fuyue'' was represented by three stars; its position is disputed and may have instead been located in [[Sculptor (constellation)|Sculptor]]. ''Tienliecheng'' also has a disputed position; the 13-star castle replete with ramparts may have possessed Nu and Xi Aquarii but may instead have been located south in Piscis Austrinus. The Water Jar asterism was seen to the ancient Chinese as the tomb, ''Fenmu''. Nearby, the emperors' [[mausoleum]] ''Xiuliang'' stood, demarcated by Kappa Aquarii and three other collinear stars. ''Ku'' ("crying") and ''Qi'' ("weeping"), each composed of two stars, were located in the same region. Three of the Chinese [[lunar mansion]] shared their name with constellations. ''Nu'', also the name for the 10th lunar mansion, was a [[handmaiden]] represented by Epsilon, Mu, 3, and 4 Aquarii. The 11th lunar mansion shared its name with the constellation ''Xu'' ("emptiness"), formed by Beta Aquarii and Alpha Equulei; it represented a bleak place associated with death and funerals. ''Wei'', the rooftop and 12th lunar mansion, was a V-shaped constellation formed by Alpha Aquarii, Theta Pegasi, and Epsilon Pegasi; it shared its name with two other Chinese constellations, in modern-day [[Scorpius (constellation)|Scorpius]] and [[Aries (constellation)|Aries]]. | 799 | Aquarius (constellation) | [
"Aquarius (constellation)",
"Constellations",
"Equatorial constellations",
"Constellations listed by Ptolemy"
] | [] |
[
"Features",
"Stars"
] | [[Image:AquariusCC.jpg|thumb|The constellation Aquarius as it can be seen by the naked eye]] Despite both its prominent position on the zodiac and its large size, Aquarius has no particularly bright stars, its four brightest stars being less than magnitude 2. However, recent research has shown that there are several stars lying within its borders that possess [[extrasolar planet|planetary systems]]. The two brightest stars, [[Alpha Aquarii|Alpha]] and [[Beta Aquarii]], are luminous yellow supergiants, of spectral types G0Ib and G2Ib respectively, that were once hot blue-white B-class main sequence stars 5 to 9 times as massive as the Sun. The two are also moving through space perpendicular to the plane of the Milky Way. Just shading Alpha, Beta Aquarii is the brightest star in Aquarius with an apparent magnitude of 2.91. It also has the proper name of Sadalsuud. Having cooled and swollen to around 50 times the Sun's diameter, it is around 2200 times as luminous as the Sun. It is around 6.4 times as massive as the Sun and around 56 million years old. Sadalsuud is 540 ± 20 light-years from Earth. Alpha Aquarii, also known as Sadalmelik, has an apparent magnitude of 2.94. It is 520 ± 20 light-years distant from Earth, and is around 6.5 times as massive as the Sun and 3000 times as luminous. It is 53 million years old. [[Gamma Aquarii|γ Aquarii]], also called Sadachbia, is a white main sequence star of spectral type star of spectral type A0V that is between 158 and 315 million years old and is around two and a half times the Sun's mass, and double its radius. Of magnitude 3.85, it is 164 ± 9 light years away. It has a luminosity of . The name Sadachbia comes from the Arabic for "lucky stars of the tents", ''sa'd al-akhbiya''. [[delta Aquarii|δ Aquarii]], also known as Skat or Scheat is a blue-white A2 spectral type star of magnitude 3.27 and luminosity of . [[epsilon Aquarii|ε Aquarii]], also known as Albali, is a blue-white A1 spectral type star with an apparent magnitude of 3.77, an absolute magnitude of 1.2, and a luminosity of . [[zeta Aquarii|ζ Aquarii]] is an F2 spectral type [[double star]]; both stars are white. Overall, it appears to be of magnitude 3.6 and luminosity of . The primary has a magnitude of 4.53 and the secondary a magnitude of 4.31, but both have an absolute magnitude of 0.6. Its orbital period is 760 years; the two components are currently moving farther apart. [[theta Aquarii|θ Aquarii]], sometimes called Ancha, is a G8 spectral type star with an apparent magnitude of 4.16 and an absolute magnitude of 1.4. [[Kappa Aquarii|κ Aquarii]], also called Situla. [[lambda Aquarii|λ Aquarii]], also called Hudoor or Ekchusis, is an [[M-type star|M2 spectral type star]] of magnitude 3.74 and luminosity of . [[xi Aquarii|ξ Aquarii]], also called Bunda, is an [[A-type star|A7 spectral type star]] with an apparent magnitude of 4.69 and an absolute magnitude of 2.4. | 799 | Aquarius (constellation) | [
"Aquarius (constellation)",
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"Equatorial constellations",
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[
"Features",
"Stars"
] | [[pi Aquarii|π Aquarii]], also called Seat, is a [[B-type star|B0 spectral type star]] with an apparent magnitude of 4.66 and an absolute magnitude of −4.1. | 799 | Aquarius (constellation) | [
"Aquarius (constellation)",
"Constellations",
"Equatorial constellations",
"Constellations listed by Ptolemy"
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[
"Features",
"Planetary systems"
] | Twelve exoplanet systems have been found in Aquarius as of 2013. [[Gliese 876]], one of the nearest stars to Earth at a distance of 15 light-years, was the first [[red dwarf]] star to be found to possess a [[planetary system]]. It is orbited by four planets, including one [[terrestrial planet]] 6.6 times the mass of Earth. The planets vary in orbital period from 2 days to 124 days. [[91 Aquarii]] is an [[orange giant]] star orbited by one planet, [[91 Aquarii b|91 Aquarii b]]. The planet's mass is 2.9 times the mass of Jupiter, and its orbital period is 182 days. [[Gliese 849]] is a red dwarf star orbited by the first known long-period Jupiter-like planet, [[Gliese 849 b|Gliese 849 b]]. The planet's mass is 0.99 times that of Jupiter and its orbital period is 1,852 days. There are also less-prominent systems in Aquarius. [[WASP-6]], a type G8 star of magnitude 12.4, is host to one exoplanet, [[WASP-6 b]]. The star is 307 [[parsec]] from Earth and has a mass of 0.888 [[solar mass]] and a radius of 0.87 [[solar radius|solar radii]]. WASP-6 b was discovered in 2008 by the [[transit method]]. It orbits its parent star every 3.36 days at a distance of 0.042 [[astronomical unit]] (AU). It is 0.503 [[Jupiter mass]] but has a proportionally larger radius of 1.224 [[Jupiter radius|Jupiter radii]]. [[HD 206610]], a K0 star located 194 parsecs from Earth, is host to one planet, [[HD 206610 b]]. The host star is larger than the Sun; more massive at 1.56 solar masses and larger at 6.1 solar radii. The planet was discovered by the radial velocity method in 2010 and has a mass of 2.2 Jupiter masses. It orbits every 610 days at a distance of 1.68 AU. Much closer to its sun is [[WASP-47 b]], which orbits every 4.15 days only 0.052 AU from its sun, yellow dwarf (G9V) [[WASP-47]]. WASP-47 is close in size to the Sun, having a radius of 1.15 solar radii and a mass even closer at 1.08 solar masses. WASP-47 b was discovered in 2011 by the transit method, like WASP-6 b. It is slightly larger than Jupiter with a mass of 1.14 Jupiter masses and a radius of 1.15 Jupiter masses. | 799 | Aquarius (constellation) | [
"Aquarius (constellation)",
"Constellations",
"Equatorial constellations",
"Constellations listed by Ptolemy"
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[
"Features",
"Planetary systems"
] | There are several more single-planet systems in Aquarius. [[HD 210277]], a magnitude 6.63 yellow star located 21.29 parsecs from Earth, is host to one known planet: [[HD 210277 b]]. The 1.23 Jupiter mass planet orbits at nearly the same distance as Earth orbits the Sun1.1 AU, though its orbital period is significantly longer at around 442 days. HD 210277 b was discovered earlier than most of the other planets in Aquarius, detected by the radial velocity method in 1998. The star it orbits resembles the Sun beyond their similar [[spectral class]]; it has a radius of 1.1 solar radii and a mass of 1.09 solar masses. [[HD 212771 b]], a larger planet at 2.3 Jupiter masses, orbits host star [[HD 212771]] at a distance of 1.22 AU. The star itself, barely below the threshold of naked-eye visibility at magnitude 7.6, is a G8IV (yellow subgiant) star located 131 parsecs from Earth. Though it has a similar mass to the Sun1.15 solar massesit is significantly less dense with its radius of 5 solar radii. Its lone planet was discovered in 2010 by the radial velocity method, like several other exoplanets in the constellation. As of 2013, there were only two known multiple-planet systems within the bounds of Aquarius: the Gliese 876 and [[HD 215152]] systems. The former is quite prominent; the latter has only two planets and has a host star farther away at 21.5 parsecs. The HD 215152 system consists of the planets [[HD 215152 b]] and [[HD 215152 c]] orbiting their K0-type, magnitude 8.13 sun. Both discovered in 2011 by the radial velocity method, the two tiny planets orbit very close to their host star. HD 215152 c is the larger at 0.0097 Jupiter masses (still significantly larger than the Earth, which weighs in at 0.00315 Jupiter masses); its smaller sibling is barely smaller at 0.0087 Jupiter masses. The [[error]] in the mass measurements (0.0032 and respectively) is large enough to make this discrepancy statistically insignificant. HD 215152 c also orbits further from the star than HD 215152 b, 0.0852 AU compared to 0.0652. On 23 February 2017, NASA announced that [[Ultra-cool dwarf|ultracool dwarf star]] [[TRAPPIST-1]] in Aquarius has seven [[Exoplanet|Earth-like rocky planets]]. Of these, three are in the system's habitable zone, and may contain water. The discovery of the TRAPPIST-1 system is seen by astronomers as a significant step toward finding life beyond Earth. | 799 | Aquarius (constellation) | [
"Aquarius (constellation)",
"Constellations",
"Equatorial constellations",
"Constellations listed by Ptolemy"
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[
"Features",
"Deep sky objects"
] | Because of its position away from the galactic plane, the majority of deep-sky objects in Aquarius are galaxies, globular clusters, and planetary nebulae. Aquarius contains three [[deep sky object]] that are in the [[Messier object|Messier catalog]]: the globular clusters [[Messier 2|Messier 2]], [[Messier 72|Messier 72]], and the open cluster [[Messier 73|Messier 73]]. Two well-known [[planetary nebula]] are also located in Aquarius: the [[Saturn Nebula]] (NGC 7009), to the southeast of [[Mu Aquarii|μ Aquarii]]; and the famous [[Helix Nebula]] (NGC 7293), southwest of [[δ Aquarii|δ Aquarii]]. M2, also catalogued as NGC 7089, is a rich globular cluster located approximately 37,000 light-years from Earth. At magnitude 6.5, it is viewable in small-[[aperture]] instruments, but a 100 mm aperture [[telescope]] is needed to resolve any stars. M72, also catalogued as NGC 6981, is a small 9th magnitude globular cluster located approximately 56,000 light-years from Earth. M73, also catalogued as NGC 6994, is an open cluster with highly disputed status. Aquarius is also home to several planetary nebulae. [[NGC 7009]], also known as the Saturn Nebula, is an 8th magnitude planetary nebula located 3,000 light-years from Earth. It was given its moniker by the 19th century astronomer [[Lord Rosse]] for its resemblance to the planet [[Saturn]] in a telescope; it has faint protrusions on either side that resemble [[Saturn's rings]]. It appears blue-green in a telescope and has a central star of magnitude 11.3. Compared to the Helix Nebula, another planetary nebula in Aquarius, it is quite small. [[NGC 7293]], also known as the Helix Nebula, is the closest planetary nebula to Earth at a distance of 650 light-years. It covers 0.25 square degrees, making it also the largest planetary nebula as seen from Earth. However, because it is so large, it is only viewable as a very faint object, though it has a fairly high [[integrated magnitude]] of 6.0. One of the visible galaxies in Aquarius is [[NGC 7727]], of particular interest for amateur astronomers who wish to discover or observe [[supernovae]]. A [[spiral galaxy]] ([[galaxy morphological classification|type S]]), it has an [[integrated magnitude]] of 10.7 and is 3 by 3 arcseconds. [[NGC 7252]] is a tangle of stars resulting from the collision of two large galaxies and is known as the Atoms-for-Peace galaxy because of its resemblance to a cartoon atom. | 799 | Aquarius (constellation) | [
"Aquarius (constellation)",
"Constellations",
"Equatorial constellations",
"Constellations listed by Ptolemy"
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[
"Features",
"Meteor showers"
] | There are three major meteor showers with [[radiant (meteor shower)|radiant]] in Aquarius: the [[Eta Aquariids]], the [[Delta Aquariids]], and the Iota Aquariids. The Eta Aquariids are the strongest meteor shower radiating from Aquarius. It peaks between 5 and 6 May with a rate of approximately 35 meteors per hour. Originally discovered by Chinese astronomers in 401, Eta Aquariids can be seen coming from the Water Jar beginning on 21 April and as late as 12 May. The [[parent body]] of the shower is [[Halley's Comet]], a [[periodic comet]]. [[Meteoroid#Fireball|Fireball]] are common shortly after the peak, approximately between 9 May and 11 May. The normal meteors appear to have yellow trails. The Delta Aquariids is a double radiant meteor shower that peaks first on 29 July and second on 6 August. The first radiant is located in the south of the constellation, while the second radiant is located in the northern circlet of Pisces asterism. The southern radiant's peak rate is about 20 meteors per hour, while the northern radiant's peak rate is about 10 meteors per hour. The Iota Aquariids is a fairly weak meteor shower that peaks on 6 August, with a rate of approximately 8 meteors per hour. | 799 | Aquarius (constellation) | [
"Aquarius (constellation)",
"Constellations",
"Equatorial constellations",
"Constellations listed by Ptolemy"
] | [] |
[
"Astrology"
] | , the Sun appears in the constellation Aquarius from 16 February to 11 March. In [[tropical astrology]], the Sun is considered to be in the sign [[Aquarius (astrology)|Aquarius]] from 20 January to 19 February, and in [[sidereal astrology]], from 15 February to 14 March. Aquarius is also associated with the [[Age of Aquarius]], a concept popular in [[1960s counterculture]]. Despite this prominence, the Age of Aquarius will not dawn until the year 2597, as an astrological age does not begin until the Sun is in a particular constellation on the [[Vernal equinox (Northern Hemisphere)|vernal equinox]]. | 799 | Aquarius (constellation) | [
"Aquarius (constellation)",
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[] | is [[Traditional animation|hand-drawn]] and [[computer animation]] originating from [[Japan]]. In Japan and in Japanese, (a term derived from the [[English language|English]] word ''animation'') describes all animated works, regardless of style or origin. However, outside of Japan and in English, ''anime'' is [[colloquialism|colloquial]] for ''Japanese animation'' and refers specifically to animation produced in Japan. Animation produced outside of Japan with similar style to Japanese animation is referred to as ''[[anime-influenced animation]]''. The earliest commercial Japanese animations date to 1917. A characteristic art style emerged in the 1960s with the works of cartoonist [[Osamu Tezuka]] and spread in following decades, developing a large domestic audience. Anime is distributed theatrically, through television broadcasts, [[Original video animation|directly to home media]], and [[Original net animation|over the Internet]]. In addition to original works, anime are often adaptations of Japanese comics ([[manga]]), [[light novels]], or [[Video games in Japan|video games]]. It is classified into numerous genres targeting various broad and niche audiences. Anime is a diverse medium with distinctive production methods that have adapted in response to emergent technologies. It combines graphic art, characterization, cinematography, and other forms of imaginative and individualistic techniques. Compared to Western animation, anime production generally focuses less on movement, and more on the detail of settings and use of "camera effects", such as panning, zooming, and angle shots. Diverse art styles are used, and character proportions and features can be quite varied, with a common characteristic feature being large and emotive eyes. The anime industry consists of over [[List of anime companies|430 production companies]], including major studios like [[Studio Ghibli]], [[Sunrise (company)|Sunrise]], and [[Toei Animation]]. Since the 1980s, the medium has also seen international success with the rise of foreign [[dubbing (filmmaking)|dubbed]] and [[Subtitles|subtitled]] programming. As of 2016, Japanese anime is accounted for 60% of the world's [[Animated series|animated television shows]]. | 800 | Anime | [
"Anime",
"1917 introductions",
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"Fandom culture in South Korea",
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"Mechademia",
"WP:SEEALSO",
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"Chinese animation",
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] |
[
"Etymology"
] | As a type of [[animation]], anime is an art form that comprises many [[genre]] found in other mediums; it is sometimes mistakenly classified as a genre itself. In Japanese, the term ''anime'' is used to refer to all animated works, regardless of style or origin. English-language dictionaries typically define ''anime'' (, ) as "a style of Japanese animation" or as "a style of animation originating in Japan". Other definitions are based on origin, making production in Japan a requisite for a work to be considered "anime". The etymology of the term ''anime'' is disputed. The English word "animation" is written in Japanese ''[[katakana]]'' as () and as (, ) in its shortened form. Some sources claim that the term is derived from the French term for animation ''dessin animé'' ("cartoon", literally 'animated design'), but others believe this to be a myth derived from the popularity of anime in France in the late 1970s and 1980s. In English, ''anime''—when used as a common [[noun]]—normally functions as a [[mass noun]]. (For example: "Do you watch anime?" or "How much anime have you collected?") As with a few other Japanese words, such as ''[[saké]]'' and ''[[Pokémon]]'', English texts sometimes spell ''anime'' as ''animé'' (as in French), with an [[acute accent]] over the final ''e'', to cue the reader to pronounce the letter, not to leave it silent as English orthography may suggest. Prior to the widespread use of ''anime'', the term ''Japanimation'' was prevalent throughout the 1970s and 1980s. In the mid-1980s, the term ''anime'' began to supplant ''Japanimation''; in general, the latter term now only appears in period works where it is used to distinguish and identify Japanese animation. | 800 | Anime | [
"Anime",
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"Fandom culture in South Korea",
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"Mechademia",
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[
"History",
"Precursors"
] | ''[[Emakimono]]'' and [[Shadow play|''kagee'']] are considered precursors of Japanese animation. ''Emakimono'' was common in the eleventh century. Traveling storytellers narrated legends and anecdotes while the ''emakimono'' was unrolled from the right to left with chronological order, as a moving panorama. ''Kagee'' was popular during the Edo period and originated from the shadows play of China. [[Magic lantern|Magic lanterns]] from the Netherlands were also popular in the eighteenth century. The paper play called ''[[Kamishibai]]'' surged in the twelfth century and remained popular in the street theater until the 1930s. Puppets of the ''[[bunraku]]'' theater and ''[[ukiyo-e]]'' prints are considered ancestors of characters of most Japanese animations. Finally, mangas were a heavy inspiration for Japanese anime. Cartoonists [[Kitazawa Rakuten|Kitzawa Rakuten]] and [[Okamoto Ippei]] used film elements in their strips. | 800 | Anime | [
"Anime",
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[
"History",
"Pioneers"
] | Animation in Japan began in the early 20th century, when [[Film director|filmmakers]] started to experiment with techniques pioneered in France, Germany, the United States, and Russia. A claim for the earliest Japanese animation is ''[[Katsudō Shashin]]'' (), a private work by an unknown creator. In 1917, the first professional and publicly displayed works began to appear; animators such as [[Ōten Shimokawa]], [[Seitarō Kitayama]], and [[Jun'ichi Kōuchi]] (considered the "fathers of anime") produced numerous films, the oldest surviving of which is Kōuchi's ''[[Namakura Gatana]]''. Many early works were lost with the destruction of Shimokawa's warehouse in the [[1923 Great Kantō earthquake]]. By the mid-1930s animation was well-established in Japan as an alternative format to the live-action industry. It suffered competition from foreign producers, such as [[The Walt Disney Company|Disney]], and many animators, including [[Noburō Ōfuji]] and [[Yasuji Murata]], continued to work with cheaper [[cutout animation]] rather than [[cel animation]]. Other creators, including [[Kenzō Masaoka]] and [[Mitsuyo Seo]], nevertheless made great strides in technique, benefiting from the patronage of the government, which employed animators to produce educational shorts and [[Japanese propaganda during World War II|propaganda]]. In 1940, the government dissolved several artists' organizations to form the The first [[talkie]] anime was ''[[Chikara to Onna no Yo no Naka]]'' (1933), a short film produced by Masaoka. The first feature-length anime film was ''[[Momotaro: Sacred Sailors]]'' (1945), produced by Seo with a sponsorship from the [[Imperial Japanese Navy]]. The 1950s saw a proliferation of short, animated advertisements created for television. | 800 | Anime | [
"Anime",
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"Fandom culture in South Korea",
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"Mechademia",
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[
"History",
"Modern era"
] | In the 1960s, [[manga]] artist and animator [[Osamu Tezuka]] adapted and simplified Disney animation techniques to reduce costs and limit frame counts in his productions. Originally intended as temporary measures to allow him to produce material on a tight schedule with an inexperienced staff, many of his [[limited animation]] practices came to define the medium's style. ''[[Three Tales (anime)|Three Tales]]'' (1960) was the first anime film broadcast on television; the first anime television series was ''[[Instant History]]'' (1961–64). An early and influential success was [[Astro Boy (1963 TV series)|''Astro Boy'']] (1963–66), a television series directed by Tezuka based on [[Astro Boy|his manga of the same name]]. Many animators at Tezuka's [[Mushi Production]] later established major anime studios (including [[Madhouse (company)|Madhouse]], [[Sunrise (company)|Sunrise]], and [[Pierrot (company)|Pierrot]]). The 1970s saw growth in the popularity of manga, many of which were later animated. Tezuka's work—and that of other pioneers in the field—inspired characteristics and genres that remain fundamental elements of anime today. The giant robot genre (also known as "[[mecha]]"), for instance, took shape under Tezuka, developed into the [[Super Robot|super robot]] genre under [[Go Nagai]] and others, and was revolutionized at the end of the decade by [[Yoshiyuki Tomino]], who developed the [[Real Robot|real robot]] genre. Robot anime series such as ''[[Gundam]]'' and ''[[Super Dimension Fortress Macross]]'' became instant classics in the 1980s, and the genre remained one of the most popular in the following decades. The [[Japanese asset price bubble|bubble economy]] of the 1980s spurred a new era of high-budget and experimental anime films, including ''[[Nausicaä of the Valley of the Wind (film)|Nausicaä of the Valley of the Wind]]'' (1984), ''[[Royal Space Force: The Wings of Honnêamise]]'' (1987), and ''[[Akira (1988 film)|Akira]]'' (1988). ''[[Neon Genesis Evangelion]]'' (1995), a television series produced by [[Gainax]] and directed by [[Hideaki Anno]], began another era of experimental anime titles, such as ''[[Ghost in the Shell (1995 film)|Ghost in the Shell]]'' (1995) and ''[[Cowboy Bebop]]'' (1998). In the 1990s, anime also began attracting greater interest in Western countries; major international successes include ''[[Sailor Moon (TV series)|Sailor Moon]]'' and ''[[Dragon Ball Z]]'', both of which were [[Dubbing (filmmaking)|dubbed]] into more than a dozen languages worldwide. In 2003, ''[[Spirited Away]]'', a [[Studio Ghibli]] feature film directed by [[Hayao Miyazaki]], won the [[Academy Award for Best Animated Feature]] at the [[75th Academy Awards]]. It later became the [[List of highest-grossing anime films|highest-grossing anime film]], earning more than $355 million. Since the 2000s, an increased number of anime works have been adaptations of [[light novel]] and [[visual novel]]; successful examples include ''[[The Melancholy of Haruhi Suzumiya]]'' and ''[[Fate/stay night]]'' (both 2006). | 800 | Anime | [
"Anime",
"1917 introductions",
"Anime and manga terminology",
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"Fandom culture in South Korea",
"Animation director",
"Japanophilia",
"Mechademia",
"WP:SEEALSO",
"Korean animation",
"Chinese animation",
"Voice acting in Japan"
] |
[
"Attributes"
] | Anime differs greatly from other forms of animation by its diverse art styles, methods of animation, its production, and its process. Visually, anime works exhibit a wide variety of art styles, differing between creators, artists, and studios. While no single art style predominates anime as a whole, they do share some similar attributes in terms of animation technique and character design. | 800 | Anime | [
"Anime",
"1917 introductions",
"Anime and manga terminology",
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"Fandom culture in South Korea",
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"Japanophilia",
"Mechademia",
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[
"Attributes",
"Technique"
] | Modern anime follows a typical animation production process, involving [[storyboard]], [[voice acting]], [[Character creation|character design]], and [[cel animation|cel production]]. Since the 1990s, animators have increasingly used [[computer animation]] to improve the efficiency of the production process. Early anime works were experimental, and consisted of images drawn on blackboards, [[stop motion]] animation of paper cutouts, and [[silhouette animation]]. Cel animation grew in popularity until it came to dominate the medium. In the 21st century, the use of other animation techniques is mostly limited to independent [[Short subject|short films]], including the stop motion puppet animation work produced by [[Tadahito Mochinaga]], [[Kihachirō Kawamoto]] and Tomoyasu Murata. Computers were integrated into the animation process in the 1990s, with works such as ''[[Ghost in the Shell (1995 film)|Ghost in the Shell]]'' and ''[[Princess Mononoke]]'' mixing cel animation with computer-generated images. [[Fujifilm|Fuji Film]], a major cel production company, announced it would stop cel production, producing an industry panic to procure cel imports and hastening the switch to digital processes. Prior to the digital era, anime was produced with [[traditional animation]] methods using a pose to pose approach. The majority of mainstream anime uses fewer expressive [[key frame]] and more [[Inbetweening|in-between]] animation. Japanese animation studios were pioneers of many [[limited animation]] techniques, and have given anime a distinct set of conventions. Unlike [[Disney]] animation, where the emphasis is on the movement, anime emphasizes the art quality and let limited animation techniques make up for the lack of time spent on movement. Such techniques are often used not only to meet deadlines but also as artistic devices. Anime scenes place emphasis on achieving three-dimensional views, and backgrounds are instrumental in creating the atmosphere of the work. The backgrounds are not always invented and are occasionally based on real locations, as exemplified in ''[[Howl's Moving Castle (film)|Howl's Moving Castle]]'' and ''[[The Melancholy of Haruhi Suzumiya (anime)|The Melancholy of Haruhi Suzumiya]]''. Oppliger stated that anime is one of the rare mediums where putting together an all-star cast usually comes out looking "tremendously impressive". The cinematic effects of anime differentiates itself from the stage plays found in American animation. Anime is cinematically shot as if by camera, including panning, zooming, distance and angle shots to more complex dynamic shots that would be difficult to produce in reality. In anime, the animation is produced before the voice acting, contrary to American animation which does the voice acting first; this can cause [[lip sync]] errors in the Japanese version. | 800 | Anime | [
"Anime",
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"Fandom culture in South Korea",
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[
"Attributes",
"Characters"
] | The body proportions of human anime characters tend to accurately reflect the proportions of the human body in reality. The height of the head is considered by the artist as the base unit of proportion. Head heights can vary, but most anime characters are about seven to eight heads tall. Anime artists occasionally make deliberate modifications to body proportions to produce [[super deformed]] characters that feature a disproportionately small body compared to the head; many super deformed characters are two to four heads tall. Some anime works like ''[[Crayon Shin-chan]]'' completely disregard these proportions, in such a way that they resemble [[caricature]] Western [[cartoon]]. A common anime character design convention is exaggerated eye size. The animation of characters with large eyes in anime can be traced back to Osamu Tezuka, who was deeply influenced by such early animation characters as [[Betty Boop]], who was drawn with disproportionately large eyes. Tezuka is a central figure in anime and manga history, whose iconic art style and character designs allowed for the entire range of human emotions to be depicted solely through the eyes. The artist adds variable color shading to the eyes and particularly to the cornea to give them greater depth. Generally, a mixture of a light shade, the tone color, and a dark shade is used. Cultural anthropologist [[Matt Thorn]] argues that Japanese animators and audiences do not perceive such stylized eyes as inherently more or less foreign. However, not all anime characters have large eyes. For example, the works of [[Hayao Miyazaki]] are known for having realistically proportioned eyes, as well as realistic hair colors on their characters. Hair in anime is often unnaturally lively and colorful or uniquely styled. The movement of hair in anime is exaggerated and "hair action" is used to emphasize the action and emotions of characters for added visual effect. Poitras traces hairstyle color to cover illustrations on manga, where eye-catching artwork and colorful tones are attractive for children's manga. Despite being produced for a domestic market, anime features characters whose race or nationality is not always defined, and this is often a deliberate decision, such as in the ''[[Pokémon (anime)|Pokémon]]'' animated series. Anime and manga artists often draw from a common canon of iconic facial expression illustrations to denote particular moods and thoughts. These techniques are often different in form than their counterparts in Western animation, and they include a fixed [[manga iconography|iconography]] that is used as shorthand for certain emotions and moods. For example, a male character may develop a [[nosebleed]] when aroused. A variety of visual symbols are employed, including sweat drops to depict nervousness, visible blushing for embarrassment, or glowing eyes for an intense glare. Another recurring sight gag is the use of [[Chibi (slang)|chibi]] (deformed, simplified character designs) figures to comedically punctuate emotions like confusion or embarrassment. | 800 | Anime | [
"Anime",
"1917 introductions",
"Anime and manga terminology",
"Japanese inventions"
] | [
"Fandom culture in South Korea",
"Animation director",
"Japanophilia",
"Mechademia",
"WP:SEEALSO",
"Korean animation",
"Chinese animation",
"Voice acting in Japan"
] |
[
"Attributes",
"Music"
] | The opening and credits sequences of most anime television series are accompanied by [[J-pop]] or [[Japanese rock|rock]] songs, often by reputed bands—as written with the series in mind—but are also aimed at the general music market, therefore it is often alluded once vaguely or not all to the thematic settings or plot of the series. Also, they are often used as incidental music ("insert songs") for each episode to highlight particularly important scenes. | 800 | Anime | [
"Anime",
"1917 introductions",
"Anime and manga terminology",
"Japanese inventions"
] | [
"Fandom culture in South Korea",
"Animation director",
"Japanophilia",
"Mechademia",
"WP:SEEALSO",
"Korean animation",
"Chinese animation",
"Voice acting in Japan"
] |
[
"Attributes",
"Genres"
] | Anime are often classified by target demographic, including , , and a diverse range of genres targeting an adult audience. Shoujo and shounen anime sometimes contain elements popular with children of both sexes in an attempt to gain crossover appeal. Adult anime may feature a slower pace or greater plot complexity that younger audiences may typically find unappealing, as well as adult themes and situations. A subset of adult anime works featuring pornographic elements are labeled "R18" in Japan, and are internationally known as ''[[hentai]]'' (originating from ). By contrast, some anime subgenres incorporate ''[[ecchi]]'', sexual themes or undertones without depictions of [[sexual intercourse]], as typified in the comedic or [[Harem (genre)|harem]] genres; due to its popularity among adolescent and adult anime enthusiasts, the inclusion of such elements is considered a form of [[fan service]]. Some genres explore homosexual romances, such as ''[[yaoi]]'' (male homosexuality) and ''[[yuri (genre)|yuri]]'' (female homosexuality). While often used in a pornographic context, the terms ''yaoi'' and ''yuri'' can also be used broadly in a wider context to describe or focus on the themes or the development of the relationships themselves. Anime's genre classification differs from other types of animation and does not lend itself to simple classification. [[Gilles Poitras]] compared the labeling ''[[Gundam 0080]]'' and its complex depiction of war as a "giant robot" anime akin to simply labeling ''[[War and Peace]]'' a "war novel". [[Science fiction genre|Science fiction]] is a major anime genre and includes important historical works like Tezuka's ''[[Astro Boy]]'' and [[Mitsuteru Yokoyama|Yokoyama]]'s ''[[Tetsujin 28-go]]''. A major subgenre of science fiction is [[mecha]], with the ''Gundam'' [[metaseries]] being iconic. The diverse [[fantasy genre]] includes works based on Asian and Western traditions and folklore; examples include the Japanese feudal fairytale ''[[InuYasha]]'', and the depiction of Scandinavian goddesses who move to Japan to maintain a computer called [[Yggdrasil]] in ''[[Oh My Goddess!|Ah! My Goddess]]''. Genre crossing in anime is also prevalent, such as the blend of fantasy and comedy in ''[[Dragon Half]]'', and the incorporation of slapstick humor in the crime anime film ''[[Castle of Cagliostro]]''. Other subgenres found in anime include [[magical girl]], harem, sports, martial arts, literary adaptations, [[medievalism]], and war. | 800 | Anime | [
"Anime",
"1917 introductions",
"Anime and manga terminology",
"Japanese inventions"
] | [
"Fandom culture in South Korea",
"Animation director",
"Japanophilia",
"Mechademia",
"WP:SEEALSO",
"Korean animation",
"Chinese animation",
"Voice acting in Japan"
] |
[
"Attributes",
"Formats"
] | Early anime works were made for theatrical viewing, and required played musical components before sound and vocal components were added to the production. In 1958, [[Nippon Television]] aired ''Mogura no Abanchūru'' ("[[Mole's Adventure]]"), both the first televised and first color anime to debut. It was not until the 1960s when the first televised series were broadcast and it has remained a popular medium since. Works released in a direct to video format are called "[[original video animation]]" (OVA) or "original animation video" (OAV); and are typically not released theatrically or televised prior to home media release. The emergence of the Internet has led some animators to distribute works online in a format called "[[original net animation|original net anime]]" (ONA). The home distribution of anime releases were popularized in the 1980s with the VHS and [[LaserDisc]] formats. The VHS [[NTSC]] video format used in both Japan and the United States is credited as aiding the rising popularity of anime in the 1990s. The LaserDisc and VHS formats were transcended by the DVD format which offered the unique advantages; including multiple subtitling and dubbing tracks on the same disc. The DVD format also has its drawbacks in its usage of [[DVD region code|region coding]]; adopted by the industry to solve licensing, piracy and export problems and restricted region indicated on the DVD player. The [[Video CD]] (VCD) format was popular in Hong Kong and Taiwan, but became only a minor format in the United States that was closely associated with [[counterfeit|bootleg]] copies. | 800 | Anime | [
"Anime",
"1917 introductions",
"Anime and manga terminology",
"Japanese inventions"
] | [
"Fandom culture in South Korea",
"Animation director",
"Japanophilia",
"Mechademia",
"WP:SEEALSO",
"Korean animation",
"Chinese animation",
"Voice acting in Japan"
] |
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