What is Orion complex?
[[File:Orion Head to Toe.jpg|thumb|right|250px|Part of the Orion complex. It shows the [[Orion nebula]] near the centre, with the ''Belt of Orion'', and ''Barnard's Loop'' curling around the image]] The '''Orion complex''' (sometimes called the '''Orion molecular cloud complex''') is a huge [[Star formation|star-forming]] area in the [[constellation]] of [[Orion (constellation)|Orion]].<ref>SIMBAD. [http://simbad.u-strasbg.fr/simbad/sim-id?Ident=orion+molecular+cloud+&NbIdent=1&Radius=2&Radius.unit=arcmin&submit=submit+id]</ref> It is a large group of bright [[nebula]]e, [[Dark nebula|dark clouds]], and young [[star cluster]]s. The cloud is between 1,500 and 1,600 [[light-years]] away and is hundreds of light-years across. Several parts of the nebula can be seen through [[binoculars]] and small [[telescopes]]. Some parts (such as the [[Orion nebula]]) are visible to the naked eye. The nebula is important because of its sheer size. It is also one of the most active regions of [[star formation|stellar formation]] that can be seen in the night sky. In it are [[protoplanetary disc]]s and many very young [[star]]s. The nebula is very bright in the [[infrared]] wavelengths due to the heat-intensive processes involved in star formation. The complex contains [[dark nebulae]], [[emission nebula]]e, [[reflection nebula]]e, and [[HII region]]s. == Nebulae in the complex == [[File:Nebula-Barnard's-Loop.jpeg|thumb|A picture of Barnard's Loop, a main part of the nebula complex. Also seen in the image are other nebulae, such as M42]] The following is a list of notable nebulae in the larger nebula complex: * The [[Orion nebula]], also known as M42 * [[M43]], which is part of the Orion Nebula * [[IC 434]], which contains the [[Horsehead nebula|Horsehead Nebula]] * The [[Horsehead nebula]] * [[Barnard's Loop]] * [[M78]], a reflection nebula * [[NGC 1999]] * NGC 2175 ** [[NGC 2174]] * Various Orion [[Molecular cloud|molecular clouds]] * [[Flame nebula]] (NGC 2024) Also the [[Orion OB1 Association]] is part of this complex