text:
2. Observations
3. Analysis and ...
Study of the inner dust envelope and stellar photosphere of the AGB star R Doradus using SPHERE/ZIMPOL
T. Khouri1,2, M. Maercker1, L. B. F. M. Waters2,3, W. H. T. Vlemmings1, P. Kervella4,5, A. de Koter2, C. Ginski6, E. De Beck1, L. Decin7, M. Min2,3, C. Dominik2, E. O'Gorman1, H.-M. Schmid8, R. Lombaert1 and E. Lagadec9
1 Department of Earth and Space Sciences, Chalmers University of Technology, Onsala Space Observatory, 439 92 Onsala, Sweden
e-mail: theokhouri@gmail.com
2 Astronomical Institute "Anton Pannekoek", University of Amsterdam, PO Box 94249, 1090 GE Amsterdam, The Netherlands
3 SRON Netherlands Institute for Space Research, Sorbonnelaan 2, 3584 CA Utrecht, The Netherlands
4 Unidad Mixta Internacional Franco-Chilena de Astronomía (CNRS UMI 3386), Departamento de Astronomía, Universidad de Chile, Camino El Observatorio 1515, Las Condes, Santiago, Chile
5 LESIA (UMR 8109), Observatoire de Paris, PSL, CNRS, UPMC, Univ. Paris-Diderot, 5 place Jules Janssen, 92195 Meudon, France
6 Sterrewacht Leiden, PO Box 9513, Niels Bohrweg 2, 2300RA Leiden, The Netherlands
7 Instituut voor Sterrenkunde, KU Leuven, Celestijnenlaan 200D B-2401, 3001 Leuven, Belgium
8 Institute for Astronomy, ETH Zurich, 8093 Zurich, Switzerland
9 Laboratoire Lagrange, Université Côte d'Azur, Observatoire de la Côte d'Azur, CNRS, Bd de l'Observatoire, CS 34229, 06304 Nice Cedex 4, France
Context. On the asymptotic giant branch (AGB) low- and intermediate-mass stars eject a large fraction of their envelope, but the mechanism driving these outflows is still poorly understood. For oxygen-rich AGB stars, the wind is thought to be driven by radiation pressure caused by scattering of radiation off dust grains.
Aims. We study the photosphere, the warm molecular layer, and the inner wind of the close-by oxygen-rich AGB star R Doradus. We focus on investigating the spatial distribution of the dust grains that scatter light and whether these grains can be responsible for driving the outflow of this star.
Methods. We use high-angular-resolution images obtained with SPHERE/ZIMPOL to study R Dor and its inner envelope in a novel way. We present observations in filters V, cntHα, and cnt820 and investigate the surface brightness distribution of the star and of the polarised light produced in the inner envelope. Thanks to second-epoch observations in cntHα, we are able to see variability on the stellar photosphere. We study the polarised-light data using a continuum-radiative-transfer code that accounts for direction-dependent scattering of photons off dust grains.
Results. We find that in the first epoch the surface brightness of R Dor is asymmetric in V and cntHα, the filters where molecular opacity is stronger, while in cnt820 the surface brightness is closer to being axisymmetric. The second-epoch observations in cntHα show that the morphology of R Dor has changed completely in a timespan of 48 days to a more axisymmetric and compact configuration. This variable morphology is probably linked to changes in the opacity provided by TiO molecules in the extended atmosphere. The observations show polarised light coming from a region around the central star. The inner radius of the region from where polarised light is seen varies only by a small amount with azimuth. The value of the polarised intensity, however, varies by between a factor of 2.3 and 3.7 with azimuth for the different images. We fit the radial profile of the polarised intensity using a spherically symmetric model and a parametric description of the dust density profile, ρ(r) = ρ°r− n. On average, we find exponents of − 4.5 ± 0.5 that correspond to a much steeper density profile than that of a wind expanding at constant velocity. The dust densities we derive imply an upper limit for the dust-to-gas ratio of ~2 × 10-4 at 5.0 R⋆. Considering all the uncertainties in observations and models, this value is consistent with the minimum values required by wind-driving models for the onset of a wind, of ~3.3 × 10-4. However, if the steep density profile we find extends to larger distances from the star, the dust-to-gas ratio will quickly become too small for the wind of R Dor to be driven by the grains that produce the scattered light.
Key words: techniques: polarimetric / stars: AGB and post-AGB / stars: individual: R Doradus / stars: winds, outflows / stars: imaging / stars: mass-loss
The asymptotic giant branch (AGB) is one of the final stages of the evolution of low- and intermediate-mass stars, when a slow and dense outflow develops (Habing & Olofsson 2003). The wind is thought to be driven by radiation pressure on dust grains that can only form because pulsations enhance the density-scale-height of the stellar atmospheres. For oxygen-rich AGB stars (where the carbon-to-oxygen ratio is lower than one), it has been proposed that large, translucent dust grains provide the required opacity and drive the wind through scattering of photons (Höfner 2008). However, many intricacies of the formation and processing of the oxygen-rich dust grains remain poorly constrained from observations. The translucent nature of these grains implies that they are not expected to produce significant infrared emission and, hence, most likely cannot be identified from infrared spectra. The best way to study such grains is through the scattered stellar light they are expected to produce.
To advance our understanding of the AGB mass loss, we use high-angular-resolution observations acquired with SPHERE/ZIMPOL (Beuzit et al. 2008) on the Very Large Telescope (VLT) to investigate light polarised through scattering off dust grains in the inner wind of the AGB star R Doradus. This oxygen-rich star with spectral type M8 has a large angular diameter in the sky (≈57 mas) and a relatively low mass-loss rate, between 0.9 and 2.0 × 10-7M⊙ yr-1 (Olofsson et al. 2002; Maercker et al. 2008; Khouri 2014). Its pulsation properties switch between one mode with a period of 332 days and ΔV = 1.5 mag, and another with a period of 175 days and ΔV< 1 mag (Bedding et al. 1998). Polarised light from a region very close to the star (≈1.5 R⋆) has been recently detected using NACO (Norris et al. 2012). The authors found that a model with grain radii of 0.3 μm and a inner radius of the dust envelope of 43.3 mas gives the best fit to the data.
Top panels: total intensity normalised using the peak flux as observed using ZIMPOL on 10- and 11-Dec.-2014 in the three filters, V, cntHα, and cnt820. Middle panels: images of the PSF-reference star ψ2 Ori normalised to the peak flux. Bottom panels: corresponding deconvolved images, again normalised using the peak flux. The dashed red circles show the size of the stellar disc derived by Norris et al. (2012) from observations in the near-infrared (same as shown in Figs. 2–5). The full red circles show the FWHM of the PSF used as reference.
Observation log.
2.1. Data acquisition and data reduction
R Dor was observed with ZIMPOL during the SPHERE science verification time using three filters, V, cntHα, and cnt820. The observations were taken in two epochs, 10 and 11 of December 2014 (V, cntHα, and cnt820) and 28 of January 2015 (cntHα). The total integration times for each filter and epoch are given in Table 1. Observations using filter cnt820 were done both with and without a neutral density (ND) filter. In the images obtained without the ND filter, the star saturated the detector. When the first-epoch cntHα images were taken the seeing was too high (>1.2′′) for an optimal behaviour of the instrument, therefore these data have to be interpreted with care.
The observations of R Dor resulted in individual data cubes, containing the frames recorded with the two cameras of the instrument (both equiped with the same filter). We processed these cubes individually using the data reduction pipeline of the instrument, in its pre-release version 0.14.01. Each cube produced Stokes + Q, − Q, + U and − U frames for the two cameras, together with intensity frames IQ and IU. We then aligned and de-rotated the resulting average frames using custom python routines. We adopt a pixel scale of 3.602 ± 0.011 mas pix-1 and a position angle of the vertical axis with respect to north of 357.95 ± 0.55 deg (Ch. Ginski, in prep.). Recently, new direction-dependent corrections to the pixel scale of less than 0.5% have been determined (see Ginski et al., in prep.). Since these are much smaller than the uncertainties from choosing the central pixel (see Sect. 3.2) for the region we consider, we have not included them.
We deconvolved the total intensity images (only) using the Lucy-Richardson (L-R) algorithm implemented in the IRAF2 software package. The point-spread function (PSF) reference images of ψ2 Ori were taken on the night of 31 March 2015, under comparable seeing conditions (σ = 0.9″) as the R Dor observations. For the cnt820 filter, we adopted the PSF observation in the TiO717 filter (with λ° = 716.8 μm and Δλ = 19.7 μm) as no other PSF observation in the cnt820 filter was available. We stopped the L-R deconvolution after 80 iterations, as the deconvolved images do not show a significant evolution in additional processing steps. Since the PSF images were not acquired simultaneously to the images of R Dor, we only show the deconvolved images to illustrate what the underlying source morphology might be. All the quantities that we present and model were extracted from the observed images and not from the deconvolved ones.
2.2. Observational results
2.2.1. The stellar photosphere
We first discuss the total intensity (Stokes I) images. The high spatial resolution achieved with SPHERE/ZIMPOL (≈20 mas) allows us to resolve the stellar disc of R Dor in the total intensity images (Figs. 1 and 2). The images acquired in the first epoch reveal a very asymmetrical source, with a horseshoe-shaped morphology both in V and in cntHα. In these images, more emission arises from the northern hemisphere and there is a region of low surface brightness in the south-west. We find an azimuthally-averaged full-width at half maximum (FWHM) in V and cntHα in this epoch of ≈71 mas (see Table 1). This asymmetric morphology is not as prominent in the cnt820 images and the source is also smaller at this wavelength, with FWHM ≈ 58.3 mas.
The surface brightness distribution of R Dor in cntHα changes between the two epochs of observation (Fig. 2). In January 2015, emission is concentrated in the central region and the intensity distribution is more axisymmetric, different from what is seen in the first epoch. In the second epoch the disc of R Dor has a FWHM ≈ 59.4 mas in cntHα. For reference, the 48 days that separate the two epochs correspond to slightly more than one-fourth of the shortest pulsation period of R Dor (175 days).
The values of the FWHM measured in the second epoch in filters cnt820 and cntHα are comparable to the stellar radius for a uniform disc obtained by Norris et al. (2012) of ≈27.2 mas, from observations that probe the stellar continuum in the near-infrared. However, the values of the FWHM in the first epoch in V and in cntHα are significantly larger than that (see Table 1).
A strong dependence of the size of the stellar disc on wavelength is a known feature of AGB stars. For instance, the measured uniform-disc diameters in the near-infrared is found to correlate with molecular spectral bands of CO and H2O (see, e.g., Wittkowski et al. 2008; Woodruff et al. 2009). In the visible wavelength range, TiO is expected to be the main source of opacity for a late-type M star as R Dor. This molecule is found to dominate the spectrum in the wavelength range of V and cntHα, but its opacity is lower in the wavelength range of filter cnt820. For comparison, molecular contribution is expected to be very small in the wavelengths that Norris et al. performed their observations. For examples of spectra of late-type stars with band identification, see, e.g., Lançon & Wood (2000).
Jacob et al. (1997) measured the diameter of R Dor in the pseudo-continuum region around 0.82 μm and in a TiO absorption band at 0.85 μm and found the stellar diameter to be 20% larger in the TiO band. Follow-up observations (Jacob et al. 2004) between 0.65 μm and 0.99 μm confirmed that the stellar disc size increases in the TiO bands. Ireland et al. (2004) found asymmetries in the stellar disc of R Dor in the same wavelength range observed by Jacob et al. (2004). The authors, however, could not determine whether these asymmetries were caused by variations in molecular excitation or in the light scattered by dust grains. Since we find that the size and the morphology of the stellar disc change considerably while the polarisation degree does not decrease significantly (see Sect. 2.2.2), we conclude that the difference in FWHM, the asymmetries, and the variation in morphology are mainly caused by variability of molecular (TiO) opacity.
The variability in TiO opacity can be caused by changes in the gas density and/or in the molecular abundance or excitation. Hydrodynamical models calculated with the code CO5BOLD (Freytag 2013) for a star with a few solar masses show that convective motions can produce large-scale density variations on time scales comparable to the one we find3. However, these models lack a realistic wavelength-dependent radiative transfer that takes into account molecular opacity. As molecular excitation, and hence the surface brightness of the stellar disc, is significantly affected by density variations, by episodic dissipation of energy carried by shocks, and by variations in the stellar radiation field, a quantitative comparison between observations and such models is not yet possible.
Top panels: total intensity normalised to unity as observed using ZIMPOL in cntHα on 10-Dec.-2014 and 28-Jan.-2015. Bottom panels: corresponding deconvolved images, again normalised to unity. The dashed red circles show the size of the stellar disc derived by Norris et al. (2012) from observations in the near-infrared (also shown in Figs. 1–5). The full red circles show the FWHM of the PSF used as reference.
Polarised intensity seen in V, cntHα, and in cnt820 on 11-Dec.-2014 and in cntHα on 28-Jan.-2015 normalised to the peak value, shown with a square-root scaling. The dashed red circles show the size of the stellar disc derived by Norris et al. (2012) from observations in the near-infrared (also shown in Figs. 1–5). The white circles (not shown for cnt820, see Sect. 2.2.2) mark the region where we find the polarised light produced in the envelope to dominate over instrumental effects.
Direction of the measured polarisation vector for the four images given in degrees relatively to the north direction. The red circles show the size of the stellar disc derived by Norris et al. (2012) from observations in the near-infrared (also shown in Figs. 1–3, and 5). The dashed blue circles enclose the regions where we find the polarised intensity produced in the envelope to be a factor of three larger than the expected instrumental polarisation (not shown for cnt820, see Sect. 2.2.2).
Polarisation degree for the four images. The red dashed circles show the size of the stellar disc derived by Norris et al. (2012) from observations in the near-infrared (also shown in Figs. 1–4). The dashed blue circles enclose the regions where we find the polarised intensity produced in the envelope to be a factor of three larger than the expected instrumental polarisation (not shown for cnt820, see Sect. 2.2.2).
2.2.2. The polarised light
Polarised light thought to be produced by scattering of stellar light off dust grains was detected from around the central star (see Fig. 3). The observed polarisation vectors are in the plane of the sky and tangential to a circle centred on the star, as expected for grains distributed in a circumstellar envelope illuminated by a central star. Figure 4 shows that the directions of the observed polarisation vectors match this expected behaviour up to distances of about 160 mas in the images obtained in the V filter, about 130 mas in the first-epoch cntHα image, and about 145 mas in the second-epoch cntHα image. At these radii the polarisation signal disappears in the noise. We did not include the observations in cnt820 in this analysis because these were either saturated or had to be acquired with a neutral density (ND) filter. The region where the detector was saturated includes the inner rim of the ring from where polarised light is seen and the ND filter can introduce uncalibrated instrumental polarisation.
The region from where we see polarised light is very similar for V and cntHα in the first epoch, but the brightness distribution is somewhat different. In V the polarised intensity is slightly more concentrated in the south part of the image (60%), while in cntHα both hemispheres show roughly the same emission with 53% of the polarised intensity originating from the southern hemisphere. There is no obvious correlation between the directions of maximum or minimum polarised intensity and those with maximum or minimum total intensity. Interestingly, although the total intensity distribution in cntHα changes drastically from one epoch to the other, the polarised intensity distribution does not change significantly. The departure from axisymmetry is stronger in January 2015 but the location of the maxima and minima of the polarised flux does not change much between the two epochs.
We divided the image in octants to facilitate our analysis and to minimise errors introduced by asymmetries of the dust envelope. Octant 1 is limited by the north and north-east directions and the numeration follows clock-wise. The value of the polarised intensity changes considerably for the different octants. In Table 2 we list the fraction of the polarised light measured per octant per filter. The ratio between the intensity from the octants with maximum and minimum polarised intensity is roughly 2.3 for V and cntHα in the first epoch and 3.7 for cntHα in the second epoch.
Fraction of the polarised flux arising from the different octants for the image in V and in cntHα.
3. Analysis and modelling of the polarised light
We now focus on our modelling efforts to derive the density radial profile of the grains that produce the scattered light.
3.1. Modelling approach
We calculated spherically symmetric models using the continuum radiative-transfer code MCMax (Min et al. 2009). The code calculates the direction-dependent scattering of radiation by dust grains and outputs images of the Stokes parameters. We convolved the Q and U images produced by the models with the PSF images. This typically caused a decrease by a factor of 1.5 of the output integrated polarised flux. This is because in the Q and U images the negative and positive lobes from a symmetrical envelope can overlap when the resolution is lowered. This leads to polarised signal in the images to cancel out. The poorer the angular resolution, the larger is the effect. The convolved Q and U images were then combined to obtain the polarised intensity for each model.
We calculated the radial profile of the polarised intensity from the observations for each octant and compared these profiles independently to the models. We considered two different envelope structures: with dust grains distributed in a thin halo with constant density (model with no outflow), and with a dust density gradient given by ρ(r) = ρ° (R°/r)n, R° being the inner radius of the dust envelope and ρ° = ρ(R°). We varied R° between 1.2 R⋆ and 2.0 R⋆ for both envelope structures and the halo thicknesses between 0.25 R⋆ and 1.5 R⋆ for the thin-halo scenario, where R⋆ = 27.2 mas (Norris et al. 2012).
We use amorphous Mg2SiO4 grains with the optical constants obtained by Jäger et al. (2003), as this dust species is one of the main candidates for driving the winds of oxygen-rich AGB stars (see, e.g., Bladh & Höfner 2012). We have also experimented with optical constants for Mg2SiO3 and Al2O3, as discussed in Sect. 4.1.2. To calculate the absorption opacities and the direction-dependent scattering properties, we approximate the actual size distribution of particle sizes by a distribution of hollow spheres (Min et al. 2003). We consider the radii, a, to be given by the standard distribution for grains in the interstellar medium n(a) ∝ a-3.5 (Mathis et al. 1977). The minimum, amin, and maximum, amax, grain radii of the distribution were varied to fit the observations (see Sect. 4.1). Our fits are only sensitive to grains with m, since smaller grains do not provide significant scattering opacity. For distributions with amin = 0.01 μm and amax between 0.2 μm and 0.5 μm, the amount of mass in grains with m is roughly between 40% and 70%.
3.2. Observational contraints
Our models only consider opacity due to dust grains, while molecular absorption may also be very important close to the star. Neglecting this source of opacity will probably cause us to overestimate the inner radius of the dust envelope. This is because photons scattered close to the star, where the gas densities are high, have a larger chance of being absorbed before escaping the envelope. Hence, the inner radius of the dust envelope would appear larger.
Instrumental polarisation may also affect the observations, though, data reduction procedures reduce it to about 0.5%. This residual instrumental polarisation mainly affects the data at projected distances >100 mas from the central source. To minimise the errors introduced, we only analysed the polarised light from the inner region up to 127 mas from the star, where the polarisation degree is larger than 1.5% and where we see the expected behaviour of the polarisation angles for the image in V and the two images in cntHα.
We fit our models to the integrated polarised fraction (IPF), the maximum polarised fraction (MPF), and the radial profile of the polarised intensity. We define the IPF as the polarised intensity integrated within a radius of 127 mas divided by the total intensity integrated over the same region. The MPF is the maximum value of the polarised fraction per octant integrated within a radius of 127 mas divided by the total intensity integrated over a circle with a 127 mas radius. These observed quantities are given in Table 1. The errors given are the 1σ uncertainties derived from the uncertainties on the polarised intensity. We also compared our models to the radial profile of the total intensity to set upper limits on the dust densities.
Comparison between the radial profile of the polarised intensity for the different octants obtained from the observations in the first epoch in V (green line) and in cntHα (red line), and in the second epoch in cntHα (blue line). The profiles were normalised using the value of the integrated polarised intensity for each filter. The octants are identified in each panel (see Sect. 2.2.2). The filled region shows the three-σ errors from combining the uncertainty given by the ESO pipeline with that from choosing the central pixels.
The IPF in the image in V is significantly smaller than those in cntHα in both epochs. The polarised signal in the first-epoch cntHα image can be affected by the not-ideal conditions when the data were taken. Specifically, the Strehl ratio in that image is different from that in the reference PSF (ψ2 Ori), which was taken under good sky conditions. This can cause more instrumental polarisation to be produced, affecting the IPF we measure. This is specially important in the regions where the polarisation degree is low (≲1%). The effect of the worse conditions can be seen in the images of the direction of the polarisation vectors (Fig. 4). The first-epoch image in cntHα shows the signal from circumstellar polarisation up to a smaller distance than the second-epoch image. This would not be expected if both images had been taken under equal conditions because in the first-epoch exposure time was longer. Nonetheless, decreasing the radius of integration from 127 mas to 110 mas only reduces the value we obtain for the IPF by a factor of 1.01. Therefore, the effect of the worse sky conditions on the IPF are not significant. Moreover, the observations in January 2015 also show a high IPF in cntHα. This leads us to conclude that the higher IPF in cntHα when compared to that in V is a real feature of the inner envelope of R Dor. However, we were not able to reproduce this wavelength dependence of the IPF with our models, which always show higher IPF in V or at most similar values of the IPF between the two filters.
An important consideration is that the measured IPF can be suppressed by molecular absorption. This is because the scattered photons travel longer through the envelope than photons that do not interact and, hence, have a higher probability of being absorbed by molecules. This causes the IPF produced by scattering off dust grains to decrease if the molecular absorption opacity increases in a given wavelength. Given these considerations, it is more likely that polarised photons in the V band are absorbed by molecules than artificially created in cntHα because of instrumental polarisation. Therefore, we consider the values measured in cntHα as more representative of the IPF produced by the dust. This approach also guarantees that we do not underestimate the dust densities we derive. Hence, we fit our models to the uncertainty-weighed-averaged IPF in cntHα from both epochs combined, of 2.35 ± 0.1%.
In order to calculate radial profiles, we need to define a central pixel but the complex morphology of the source makes this determination difficult. For reference, the FWHM of R Dor in the total intensity images in V is of roughly 20 pixels (72 mas, see Table 1). We have chosen the central pixel in the images in V as the one more closely equidistant from the peak of polarised light for different azimuths. The central pixels in the other filters were chosen by establishing the best match when overlaying the polarised-light images with those in V. By following this approach, we find that the chosen central pixels differ from the centre of light by a distance of one (3.6 mas) or two pixels (7.2 mas) for the images in V and in both epochs in cntHα. The pixels where the total intensity peaks differ from our chosen central pixel by a distance of between 3 (10.8 mas) and 4 pixels (14.4 mas) for the image in V and the first-epoch image in cntHα. For the second-epoch image in cntHα, in which the stellar disc is more axisymmetric, the intensity peaks on our chosen central pixel. These considerations support our approach for determining the central pixel. The uncertainty caused by the choice of the central pixel on the derived radial profiles of the polarised intensity was taken as the maximum difference between considering the chosen central pixels or one of its eight neighbouring pixels. This approach overestimates the uncertainty on the slope of the radial profile of the polarised intensity. The effect of considering different central pixels on the IPF and MPF is negligible compared to the uncertainty of the measurements.
In Fig. 6 we compare the radial profiles for the eight octants in the images in V and in cntHα. The profiles were normalised using the integrated polarised intensity for each filter. The radial profiles obtained from the three images are very similar and agree well within the uncertainties. The fact that the profiles from cntHα in the first epoch deviate slightly from the other two for r ≳ 3 R⋆ can be attributed to the worse conditions when those observations were taken and to a higher instrumental polarisation.
We were not able to determine the particle size from the wavelength dependence of the scattering. This is because of the expected contribution of molecular opacity in the wavelength range of the observations that can disrupt the wavelength dependence imprinted by scattering. We infer that molecular opacity is important in the first epoch because of the higher IPF in V than in cntHα, which we are not able to reproduce with our dust model.
We fit the IPF of 2.35 ± 0.1% and the radial profiles within 127 mas (5 R⋆, see Sect. 3.2) measured in the first epoch in V and in the second epoch in cntHα. This means that our results are limited to a small region around the star. For reference, material moving outwards at the maximum gas expansion velocity, of 5.7 km s-1, would take roughly five years to cross the region we probe. We also used the radial profile of the total intensity from the second-epoch observations in cntHα to set an upper limit on the dust densities allowed by the models. Finally, we investigated whether a high value of ρ° is enough to reproduce the MPF.
4.1. The integrated polarised fraction and the radial profile of the polarised intensity
Optical-depth effects become important when we consider grain size distributions with maximum radii, amax, between 0.2 μm and 0.5 μm. For these values of amax, our models require an average optical depth, τV, 1 to reproduce the observed IPF. In the optically-thick regime our fit parameters, ρ°, R°, and n cannot be determined independently.
Typically, the IPF we obtain from our models is larger the larger the dust mass within the region of integration (127 mas). However, when , increasing ρ°, and hence the dust mass, does not lead to a larger IPF because of the effect of multiple scattering. Also, for , the peak of the radial profile of the polarised intensity becomes broader and shifts to larger radii, in comparison to optically-thin models. This causes models with to require smaller values of R° and larger values of n, when compared to optically-thin models. Our models with require R° = 1.45 ± 0.1 R⋆ and (with an average best-fitting value of n ≈ 4.5) to fit the radial profile of the polarised intensity. A model with τV ≈ 3.5 requires R° ≈ 1.2 and n ≈ 5.5 instead.
Observed azimuthally-averaged radial profile of the total intensity in the second-epoch cntHα images (full black line) compared to models with τV = 0.65, R° = 1.5 R⋆, and n = 4 (dashed red line), τV = 1.3, R° = 1.45 R⋆, and n = 4.5 (dotted green line), and τV = 1.9, R° = 1.4 R⋆, and n = 5 (dotted-dashed blue line). The values of R° and n for each of the dust models shown have been determined by fitting the radial profile of the polarised intensity. For reference, we also show the radial profile of our model star with no dust envelope (double-dashed purple line).
Comparison between the radial profile of the polarised intensity obtained from models and from the observations in V (black line) for the different octants. Octant one is limited by the north and north-east directions and the numeration follows clock-wise. The grey-filled region shows the three-σ errors from combining the uncertainty given by the ESO pipeline with that from choosing the central pixel. The different octants are identified by number in each panel (see Sect. 2.2.2). We show the best fit models for: a thin halo (pink line), n = 5 (cyan line), n = 4 (red line), n = 3 (green line), and n = 2 (blue line). The filled regions around the model lines show variation with direction introduced by the convolution with the PSF.
4.1.1. Constraints from the total intensity images
Although we do not attempt to fit the unpolarised surface brightness of R Dor, we use the radial profile of the total intensity to set an upper limit on the scattering optical depth of the envelope. The first-epoch images do not offer strong constraints because the stellar disc is seen to be very large in that epoch both in V and in cntHα. However, as shown in Fig. 7, the second-epoch images in cntHα do offer important constraints. Optically-thick models overpredict the total intensity for all distances from the star. Optically-thin models also overpredict the total intensity for mas but that is because our limb-darkened stellar model is not accurate enough to reproduce the brightness distribution of the stellar disc. Since the polarised fraction in cntHα does not seem to decrease from the first to the second epoch, we conclude that this limit on τV applies to both epochs. This reinforces the conclusion that the variability and asymmetries in the total intensity images in the first epoch are caused by molecular opacity. We conclude that models with scattering optical depths 1.2 do not provide acceptable fits to the data.
Moreover, the value derived by Norris et al. (2012) for the inner radius of the dust envelope of R Dor, of R° = 1.6 R⋆, is in better agreement with what we obtain for models with . Since the scattering opacities in the wavelengths of the observations of Norris et al. are roughly one order of magnitude lower than those in the wavelength range of our observations, it is unlikely that their results are affected by high scattering optical depths in the envelope. This reinforces the conclusion that optically-thin models are preferred.
4.1.2. Larger grain sizes and different dust species
We have tested the effect of increasing amax to values between 0.6 μm and 1.0 μm. We find that such models produce lower values of the IPF for a given optical depth, when compared to models with smaller values of amax. Therefore, the effects of high τV are stronger the larger amax, for m.
We have also experimented using optical constants for amorphous Al2O3 (Koike et al. 1995) and MgSiO3 (Dorschner et al. 1995), with all other parameters kept constant. We find IPF values that differ only by a few percent from those obtained using Mg2SiO4. We conclude that the effect of the assumed grain species on our results is small.
Calculated reduced-χ2 values of the models shown in Fig. 8 fit to the radial profiles measured in the V filter for each octant.
Best-fit models for the radial distribution of scattering grains using different minimum and maximum grain sizes.
4.1.3. The radial profile of the dust density
The best-fits to the observed radial profile measured in V are shown in Fig. 8. In Table 3, we show reduced-χ2 values for these same models fit to the normalised profile of the observed polarised flux. As can be seen, models with dust grains confined to a thin halo are not able to reproduce the observations for , while models with have dust density profiles that are too shallow and that overpredict the observed polarised intensity also for . The dust density profiles we find are not sensitive to the size of the particles we consider, as long as the optical depth in the visual, τV, does not vary.
The best-fitting values of τV and ρ° for models with different minimum and maximum grain sizes are given in Table 4. The dust density profiles (n ≈ 4.5) we obtain are steeper than that of a wind expanding with constant speed (n = 2). This can be the result of acceleration, of destruction of the dust grains in the observed region, of a decreasing mass-loss rate on short time scales, or be caused by the density structure imprinted by consecutive shock waves in the inner envelope, as predicted by 1D wind-driving models (see, e.g., Höfner et al. 2003, for gas density profiles from models for carbon-stars).
Ireland et al. (2005) observed polarised light from two low-mass-loss rate and oxygen-rich AGB stars, R Car and RR Sco, and found that the data was better reproduced by a model with a central star surrounded by a thin shell, instead of an outflow. If these sources also have steep density profiles in the inner wind, the structure they interpreted as a thin shell might actually be the edge of a dust envelope similar to that of R Dor.
Our models produce values of the scattered-light fractions in the near-infrared roughly a factor of 3.5 larger than those reported by Norris et al. (2012) for R Dor. It is not clear whether this is caused by variability of R Dor between the times of the two observations, by systematic errors in the data acquisition methods, or by differences in the models used by us and by Norris et al. to derive these quantities.
4.2. The maximum polarised fraction
We estimated the variation in ρ° required to reproduce the difference in the observed polarisation degree between the octants. We are not able to reproduce the MPF in cntHα (>3%) with models that have because the model envelopes become too optically thick and do not reach such high polarised fractions. By considering amax = 0.1 μm we are able to fit the observed IPF with much lower maximum optical depths of ≈0.2 and we are, then, able to reproduce the MPF.
Norris et al. (2012) report grains of 0.3 μm in the outflow of R Dor. This value is in the range of grain radii for which we cannot reproduce the MPF.
4.2.1. Tangential optical depths
Given the considerable optical depths in the wavelengths we observe, asymmetries can cause tangential optical depths in the envelope to be significantly different from those in our spherically symmetrical model. The tangential optical depths are measured along the line-of-sight and in the direction of the observer between the plane of scattering and the outer edge of the envelope. For lines-of-sight with lower tangential optical depths, more polarised photons can escape. In this case, the MPF could be reproduced by an envelope with grains with amax ≳ 0.2 μm and tangential optical depths varying with azimuth. In order for the polarised intensity from one octant to be a factor of 1.5 higher than that of a spherically symmetric model, the tangential optical depth would have to be 0.4 smaller. Given that the optical depths we find are of order unity, this would imply a decrease of the tangential optical depth of roughly 40% for the octants with maximum polarisation. Since the polarised fraction would depend on both the tangential optical depth and on ρ° for each octant for non-spherically-symmetric envelopes we have not explored this possibility further.
4.3. Comparison with ZIMPOL results for W Hya
Ohnaka et al. (2016) reported SPHERE/ZIMPOL observations of the O-rich AGB star W Hya that resolved the direct stellar emission and the region in the close circumstellar environment where polarised light is produced. The authors find large grain sizes (~0.5 μm) and small optical depths, of 0.1, in visual wavelengths. These are very different from our preferred models for R Dor, with optical depths in visible wavelengths of ~1. Since the polarisation degree reported by Ohnaka et al. for W Hya is comparable to what we find for R Dor and the mass-loss rate of W Hya (of ~ 1.3 × 10-7M⊙ yr-1, Khouri et al. 2014) is similar to that of R Dor, the differences between the results reported by Ohnaka et al. and ours are not expected.
Ohnaka et al. used a non-spherically symmetric radiative transfer model to reproduce the observations. This might affect the derived optical depths because the tangential optical depths can be considerably different from a spherically symmetric model (see Sect. 4.2.1). Moreover, the authors constrained the dust mass also taking into account the scattered light fractions reported by Norris et al. (2012) for W Hya. Therefore, the differences in the derived optical depths might be related to the fact that we overpredict the scattered light fractions given by Norris et al. for R Dor (see Sect. 4.1.3). However, we are not able to determine the cause of these discrepancies and further investigation is needed.
We note that if our models underestimate the polarised flux for a given value of the optical depth of the envelope, the dust densities we find will be overestimated. Hence, the actual dust densities and the dust-to-gas ratio in the envelope will be smaller than the values we report.
4.4. Dust grains as wind drivers
We now investigate whether the grains we see around R Dor are sufficient for driving the wind. Wind-driving models indicate that the minimum dust-to-gas ratio (d/g) for a wind to develop is d/g ≈ 6 × 10-4 (Höfner 2008) or even d/g ≈ 3.3 × 10-4 (Bladh et al. 2015)4. These models consider grains of a single radius, which is typically 0.2 μm.
We estimate an empirical upper limit for the d/g at a radius r in the envelope of R Dor by considering a lower limit for the gas density, , and the dust density profiles we find. We use the parameters commonly obtained for the gaseous outflow of R Dor of and υ∞ = 5.7 km s-1 (see, e.g., Khouri 2014). This should give us a robust lower limit on the gas densities, since the gas expansion velocities are expected to be smaller than υ∞ close to the star.
For the dust density profile, we use n = 4.5 and the average density from the model with only large grains, ρ° = 3 × 10-18 g cm-3, as this is the model more directly comparable to the single-grain-size models of Höfner and Bladh et al. This choice should not have a strong effect on our results because, at a given distance from the star, all our best-fitting models have densities of grains with a ≧ 0.15 μm which are always smaller or very similar to that of the model with only large grains.
We find d/g ≦ 5 × 10-3 at r = 1.5 R⋆ and d/g ≦ 2 × 10-4 at r = 5.0 R⋆. Although the upper limit for the d/g we derive at r = 1.5 R⋆ does not provide strong constraints, the low value for the upper limit at r = 5.0 R⋆ shows that at that radius the d/g in the outflow of R Dor is close to the limit of what wind-driving models require. We note that our results can underestimate the dust densities if the polarisation efficiency of the grains is overestimated by our model. However, this would imply higher scattering optical depths for the envelope, which our results disfavour. Given the low expansion velocity and mass-loss rate of R Dor, a low value of the d/g is not unexpected. However, if the steep radial profile of the dust density extends beyond 5 R⋆, the d/g would soon become too low for the dust to provide the required opacity to drive the outflow. This would be a problem because the maximum expansion velocity of the outflow of R Dor only equals the escape velocity of a 1 M⊙ star at r ≈ 35 R⋆, and hence the radiation pressure force would have to be larger than the gravitational pull up to that distance.
We have observed the oxygen-rich AGB star R Dor using SPHERE/ZIMPOL on the VLT in three filters: V, cntHα, and cnt820. Observations in cntHα were acquired in two epochs 48 days apart. The stellar disc is resolved in all observations and we are able to study asymmetries and variability in the star. We find the total intensity distribution of R Dor to have a horseshoe-shaped morphology in the first epoch both in V and in cntHα. In the pseudo-continuum filter cnt820 the stellar disc is smaller and any departures from axisymmety are much less pronounced. In the second-epoch, taken 48 days later, the image in cntHα shows a source with a very different morphology. Moreover, the stellar disc is significantly smaller than in the first-epoch image in the same filter and is comparable in size to what we see in cnt820, also in the first epoch. We interpret these differences in size and morphology as being caused by variability in the excitation and/or density of TiO molecules in the extended atmosphere of the star.
We detect polarised light coming from a ring that encloses the central source and that spans a similar region in the three images we consider, in V and the two epochs in cntHα. However, the polarised intensity varies significantly with azimuth for the three images and the ratio of the polarised intensity between two images also varies somewhat with azimuth. We find the integrated polarised fraction in V to be smaller than those in cntHα in the two epochs and the integrated polarised fraction to increase in cntHα from the first to the second epoch. Our fits to the integrated polarised fraction and the radial profile of the polarised intensity show that we see outflowing dust grains. Considering models with dust density profiles of the type ρ(r) = ρ°r− n, we find that the dust density decreases much more steeply with radius than expected for a wind expanding at constant speed. This can be caused by the acceleration of the wind, but could also be explained by destruction of the dust grains or by a varying mass-loss rate on short time scales.
We use our best-fitting dust models and literature values for the gaseous outflow to calculate upper limits for the dust-to-gas ratio as a function of radius. We compare the limits we obtain to results from wind-driving models and we find that the upper limit we derive for the dust-to-gas ratio at 5 R⋆ is somewhat lower than the minimum values required by such models for a wind to develop. Given the approximations we use for the grain model and the envelope structure, the upper limit we find for the dust-to-gas ratio is consistent with the value found in wind-driving models. However, if the steep dust density gradient we derive extends to larger radii, the dust-to-gas ratio would surely become too small for the outflow to be driven. Given the low expansion velocity of the outflow of R Dor, the wind only reaches the escape velocity of a one solar mass star about 35 R⋆ from the central star. Therefore, if the grains we see are the main source of opacity that drives the wind, we would expect a flattening in the power law of the dust density profile not much farther out than the maximum radius we probe.
Further investigation of the outflow of R Dor will help to better understand how its wind is accelerated. Particularly, deeper observations using ZIMPOL can probe the dust density farther out in the envelope to better constrain the role of the scattering grains in driving the wind. Similar studies for other AGB stars will show whether what we see for R Dor is representative in any way and how the distribution of the dust in the inner wind changes for different stars. This will help advance our knowledge of the driving of AGB outflows and of the AGB evolution in general.
Downloadable from ftp://ftp.eso.org/pub/dfs/pipelines/sphere/
http://iraf.noao.edu
See http://www.astro.uu.se/~bf/ for the model results.
Both studies report silicon condensation fractions. We calculated the d/g by adopting solar silicon abundances (Asplund et al. 2009).
This work was supported by the Swedish Research Council. M.M. has received funding from the People Programme (Marie Curie Actions) of the EUs FP7 (FP7/2007−2013) under REA grant agreement No. 623898.11. W.V. acknowledges support from ERC consolidator grant 614264.
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text:
Šumanovci su naselje u Republici Hrvatskoj u Požeško-slavonskoj županiji, u sastavu grada Kutjeva.

Zemljopis
Šumanovci su smješteni 17 km istočno od Požege na cesti prema Našicama, susjedna sela su Cerovac na zapadu i Tominovac na istoku.

Stanovništvo
Prema popisu stanovništva iz 2011. godine Šumanovci su imali 139 stanovnika.

Pitanje oko imena
Stanovnici još uvijek nisu sigurni u vezi imena sela. Na jednome natpisu sela piše "Šumanovci", a na drugome piše "Šumanovac". Također se na raznim dokumentima nalaze oba imena. U jednoj karti vojne surveje Slavonske provincije (1781. – 1783.) se Šumanovac zapisao kao "Shumanowacz" što daje težinu imenu "Šumanovac".

Izvori

Naselja u Požeško-slavonskoj županiji

redpajama_set_name: RedPajamaWikipedia


Gaysky Mining and Processing Works has put into operation a new floatation machine.
The SOMEX machine has been assembled at the main premises of the processing factory replacing outdated machinery.
"The new machine is twice smaller than its predecessor. Each of its six compartments has the volume of 25 cubic meters as opposed to 50 cubic meters of the previous machine. That's because the processing technique has changed, and we no longer need machines with such large compartments", the factory chief engineer Alexei Vinokurov said.


text:
Well if you played SingStar……
Sorry folks meant to do more but that winter storm nailed us on the power seen for the last week. That being said I want to talk about the SingStar game for the PlayStation. This game original came out for the PS2 and is still going strong on the PS3. This game will introduce most Americans to a group of bands that they may be unfamiliar with.
Case in point. Gotthard from Switzerland. I found a little more when my cousins were here from Germany. They filled me in on all the groups that I had never heard of before but was beginning to like alot. So I will slowly be sharing many of these bands with you in the coming months. Now back to Gotthard.
From there website Gotthard Offical:
The story so far…..
13 No.1 albums
1 Diamond Award (1 million albums sold in Switzerland)
1 Tripple platinum album (Homerun)
5 Double Platinum albums (Human Zoo, One Life One Soul, Open, DeFrosted, Lipservice)
6 Platinum albums (Gotthard, Dial Hard, G. One Team One spirit, Made In Switzerland, Domino Effect)
1 No. 1 single (Heaven)
6 Top ten singles
1 Gold single (Heaven)
More than 2 million albums sold world wide.
Impressive to say the lest. I was sadden to learn that the lead singer I was getting used to on SingStar had died in Oct 2010. Steve Lee who was one of the founders of the band died in a motorcycle accident in the US.
The band came onto the scene in 1992. This year they released a new album in Sept. called "Homegrown – Alive In Lugano" which contains vocals done by the late Steve Lee at a concert they did in July of last year before his death. I must say every album of their I have found has been a hit with me. Hope to see more of them as the years keep rolling on.
This entry was posted on October 29, 2011 by heishort. It was filed under Metal, Rock and was tagged with Gotthard, Heavy Metal, Playstation, Rock, SingStar, Swiss Band.

redpajama_set_name: RedPajamaCommonCrawl


text:
FK Klaipėdos Granitas (lit. Futbolo Klubas Klaipėdos Granitas) – nieistniejący litewski klub piłkarski, mający siedzibę w Kłajpeda, w zachodniej części kraju.

Historia
Chronologia nazw:
 2012—...: FK Klaipėdos Granitas

Klub został założony na początku 2012 roku jako FK Klaipėdos Granitas. W debiutowym sezonie 2012 klub zajął 4 miejsce w drugiej lidze i awansował do pierwszej ligi. W sezonie 2013 uplasował się na 1. miejscu i po raz pierwszy zdobył awans do najwyższej ligi Mistrzostw Litwy. W 2016 został rozwiązany.

Sukcesy

Trofea międzynarodowe
Nie uczestniczył w rozgrywkach europejskich.

Trofea krajowe

 mistrz I ligi: 2013

Stadion
Klub rozgrywa swoje mecze domowe na stadionie Centralnym w mieście Kłajpeda, który może pomieścić 4 940 widzów.

Przypisy

Bibliografia
 Oficjalna strona klubu

 Profil na UEFA

Nieistniejące litewskie kluby piłkarskie
Kluby piłkarskie założone w 2012
Kluby piłkarskie rozwiązane w 2016
Sport w Kłajpedzie


text:
Doctor Strange in the Multiverse of Madness (2022) review
Dir. Sam Raimi
The single best thing about Doctor Strange in the Multiverse of Madness is that Marvel allowed Sam Raimi to exercise his vision. At least some of it. The framework of the tried-and-true Marvel formula still lives within the latest work of the superhero factory, but it at least affords an idiosyncratic stylist the opportunity to inject flavorings of body horror and disturbing imagery into the mix.
That said — and I'm willing to bet even Marvel didn't envision this — Doctor Strange's first sequel is still the second-best multiverse movie in most theaters in which it's playing.
The film properly reacquaints us with Stephen Strange (Benedict Cumberbatch), whose own fumblings opened up a part of the multiverse in Spider-Man: No Way Home. Sucked into the multiverse is America Chavez (Xochitl Gomez), a teenager who first appears in Strange's dreams before he saves her in real-life when Manhattan gets destroyed by an eyeball with tentacles — a creature likely ripped from Raimi's latest nightmare.
Both Strange and Wong (Benedict Wong) learn from America that she can hop from one universe to another despite the fact she's powerless when it comes to controlling such an ability. Because we always need a baddie looking to use the next inexplicable piece of universe-bending technology for evil, insert Elizabeth Olsen's Scarlett Witch, a rogue Avenger. This is where you'll need to be familiar with the Disney+ series WandaVision in which the titular Wanda Maximoff (Olsen) used her powers to create an artificial reality that resembled a 1950s sitcom, where her and her late husband could live out their life.
This is part of the reason my interest in Marvel has waned over the past few years. Ever since the inception of Disney+, there are four streaming series released in any given calendar year. It's come to the point now where you need to watch those in order to be aware of the basic premise of the latest movie. The evolution of Marvel as a franchise has mirrored that of video-games. You can't just pick up and play one. You have to be inundated with backstory coupled with plot interworkings spanning spin-off installments that have mostly eluded me since, I dunno, Avengers: Infinity War?
That doesn't make Doctor Strange in the Multiverse of Madness any less of a visual experience. The very essence of Strange's character permits filmmakers to build up a world before letting it crumble to shreds. Raimi doesn't hold back in showing the ceaseless effects of the multiverse. Cinematographer John Mathieson (Detective Pikachu) is tasked to keep up with the craziness, and does so admirably — perhaps no better than when Strange and America find themselves falling through multiple universes at once, each one characterized by different cityscapes. Danny Elfman's score doubles down on the hallucinatory effect all of this madness creates.
I wanted a bit more madness in general. Where the film gets bogged down is in its incessant desire to have characters explain the plot — a sign of the over-complicated, intertwined narratives Marvel has created for itself. Doctor Strange in the Multiverse of Madness is at its most enjoyable when the worlds begin collapsing into themselves, hurling Strange and America through one logic-defying universe after another. Meanwhile, Olsen is pleasantly dynamic as is Rachel McAdams, Strange's former lover.
One commendable element I didn't see coming: the film has a relatively quiet ending as opposed to a noisy one. That was unexpectedly refreshing. I also won't spoil the cameos. I'll just say Evil Dead fans will smile ear-to-ear when one familiar face makes an appearance.
Raimi drags us to hell(s) when he can, but the film is mostly defined by a thick plot and a screenplay (by Michael Waldron, Loki) that buries its characters into the spices on an "Everything Bagel" that isn't as delectable as I hoped. Doctor Strange in the Multiverse of Madness is brought to life in many ways by the work of a director looking to make a horror comic of sorts. It's a shame he got saddled with a simultaneously flimsy yet bloated script.
NOTE: Doctor Strange in the Multiverse of Madness is now playing exclusively in theaters.
My review of Doctor Strange
Starring: Benedict Cumberbatch, Xochitl Gomez, Elizabeth Olsen, Benedict Wong, and Rachel McAdams. Directed by: Sam Raimi.


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Docker container for Pastec

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- Add ability to load an index file to docker entrypoint

redpajama_set_name: RedPajamaGithub


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North Carolina man wins second lottery jackpot in 7 months
A North Carolina man won $200,000 from a scratch-off lottery ticket just 7 months after collecting a $50,000 prize. File Photo by John Angelillo/UPI | License Photo
July 11 (UPI) -- A North Carolina man who won a $50,000 jackpot from a scratch-off lottery ticket in January had luck strike a second time in the form of a $200,000 prize.
Roger Lunsford of Swannanoa told North Carolina Education Lottery officials his shock at scratching of a $200,000 top prize from the All About The Bens ticket he purchased from Stop N Go in Swannanoa was compounded by the fact that he had just won $50,000 from a $10,000,000 Colossal Cash ticket in January.
"I'm not one of those folks that jumps up and down and hollers," Lunsford said. "But I was shocked when I saw that I had won again, and how much it was."
"It was definitely a lot to take in," he said.
Lunsford said his latest winnings will go into a "rainy day" fund and will potentially finance some future family trips.
"We want to take a vacation to Florida," he said. "I love fishing and it's so nice out on the water there."
Connecticut man wins his second $100,000 lottery jackpot World Cup inspires woman's losing lottery ticket world record attempt Wisconsin man claims $5.9M jackpot 10 days before lottery ticket expired
Man's long lucky lottery streak culminates in $1 million jackpot
Emu spotted running loose though North Carolina counties
Texas family upset by breast-baring photobomber
Postcard shows up at Illinois home exactly 26 years after postmark


This isn't the first time our characters reached their hands, claws and paws out to Hollywood. In the 1960s, General Mills and Hollywood teamed-up on a first-of-its-kind media and shows division dedicated to creating children's animated TV shows.
General Mills' media and shows division worked directly with studios such as Hanna-Barbera and Total Television to create and distribute fully-produced half-hour cartoon shows to television stations.
Toys, games and puzzles inside our cereals boxes continued to bring these stories and characters to life in even bigger ways.
Two years later, in a nod to the growing popularity of Bullwinkle the Moose, the show was moved to evenings on NBC.
The moose-and-squirrel cartoon introduced other irreverent cartoon favorites such as Underdog, Dudley Do-Right and Mr. Peabody.
Not only was this original marketing effort ahead of its time; several of General Mills' animated cartoon programs are considered true cult classics.
We're looking forward to working with you to create the next cult classic.
In 1979, children dug inside specially-marked boxes of Count Chocula, Frankenberry and Boo Berry cereals to discover a flexi-record featuring the very first Monsters and Hollywood collaboration. "Monster Adventures in Outer Space" took kids to the farthest reaches of the known cosmos. "Count Chocula Goes To Hollywood" brought our Monsters right into the heart of the entertainment industry, and "The Monsters Go Disco" introduced our timeless Monsters to the dance-driven vibe of the times.
Now we're back and ready to work with you to write the next great Hollywood blockbuster.
Click here to work with us.


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First off what is rambutan? Where does it come from? Rambutan is an edible fruit that grows on the tree by the same name. It comes from the Malay-Indonesian region and other parts of Southeast Asia. We are going to talk about the benefits of this tropical fruit. It is believed the fruit flourishes in warm, tropical climates. Now, that we know a little bit more about rambutan let us review some of the top-rated products.
Let's define hibiscus tea before we start looking for the health benefits of this tea. Hibiscus tea is a herbal tea made from the deep red crimson-colored hibiscus flower. If you have ever drunk a cup of this organic tea you would know it. You simply would not miss its bright red color. Is it a popular tea to consume is a question that is still up in the air. But we are not here to discuss its popularity or not. We just want to know what are the best hibiscus tea products available on the market today. Let's start exploring that all-important issue of which are the best hibiscus tea brands available.
Essential oils are substances that are stored either inside of plants or in glands on their leaves. They are extracted from plants by a process of steam distillation, and the extracted oil is a very potent source of active compounds that play an important role in plants and provide us with plenty of benefits too.
The first question to ask is are quail eggs safe for humans to eat? If so what health benefits can we derive from eating quail eggs? What do quail eggs taste like? It is uncommon to eat quail eggs because you do not hear about people eating quail eggs every day. There may be different parts of the world where this is a delicacy but in the United States, it is rare for people to eat quail eggs for health benefits or for any benefits for that matter.


The LG-built Nexus 5 is a wonderful phone. Before it landed, many complained that the screen would be too big, and the overall size of the device would be prohibitively large for a smartphone. In the year since its been around, however, the Nexus 5 has proven to be very usefully sized, without being too large to comfortably carry. Now that we're getting close to when we suspect the "Nexus 6" will launch, we're hearing rumors that it may be called the "Nexus X" and codenamed the Motorola Shamu.
If what we've pieced together holds true, the Motorola Shamu will be Google's first Nexus phablet. Reports are that it will feature a 5.92-inch screen, with battery, processor, and RAM to match. That's almost a full diagonal inch larger than the Nexus 5.
Who would ever want a phone that big? You'll look like you're talking into a piece of toast. 640KB ought to be enough for anyone!
Look at the trend in mobile devices these days. Tablets, which once were in the 10- and 11-inch ballpark, are now settling down the 7-inch range. Phones, which used to be around 3.5-inches, are slowly creeping up – 5-inches is "average" these days.
The Samsung Galaxy Note 3 and Note 4 have a screen that's 5.7-inches. Apple's iPhone 6 Plus sports a screen size of 5.5-inches. Both the Note line and Apple's larger iPhone are enjoying a significant amount of popularity, not despite the size of their screens, but because of it. The screen on the Motorola Shamu should prove to be even even larger, and perhaps even more popular.
That still makes us ask who large-screened smartphones and phablets appeal to?
It didn't even have an Internet connection!
I'm a very busy guy. I get up in the morning and go to work on my desktop computer. When I'm done there I head off to my day job and work on another computer. When I take a lunch I usually pull out my smartphone or tablet and work some more.
Back at my day job I jump between meetings all across the corporate campus, smartphone and tablet in tow. When I get back home, I spend some much needed time with my family, often watching shows that I cast to the big screen from my smartphone or tablet via my Chromecast. After that it's back to work on the computer for another few hours before I finally hit the sack.
That's a lot of equipment that I've got to pack around. My smartphone, even at 4.95-inches, isn't big enough to get all my work done. I can email, schedule appointments, and do some research, but for me to get any real work done, I've got to have something bigger. My Nexus 7 tablet is almost perfect for this task, but it's not a phone, and I don't feel like paying for another line of service just for it, so I tether it to my smartphone for Internet access. This results in me packing around two devices where I could probably make do with just one – if it were big enough.
Students do a lot of writing, a lot of reading, and watch a lot of movies when they should probably be studying. Again, this is where a larger screen really helps out. Throw a Bluetooth keyboard into the mix, like the Logitech K480, and you've got an instant mobile workstation, big enough to get some papers written or notes typed, but small enough to be convenient enough to pack with you.
Gaming and movie watching on a large-screened device are much more enjoyable than on a smaller screen, and let's face it, we all did a lot of gaming and movie watching as students.
Manufacturers are making the push to 4K screens, whether we "need" them or not. Screens with that many pixels are going to be bigger than those with fewer pixels, at least of the time being. As screen technology improves, who knows, we may see a 4K 3.5-inch screen, but what would be the point at that size?
Should the rumors turn out to be true, the Motorola Shamu is ultimately built for you. It's big enough to be as convenient and useful as a tablet, but small enough to be carried around like a phone. We may not feel the same way once it's finally here, but until then, the Motorola Shamu looks like it might just be the perfect size for everyone – as long as you don't have small hands.


Today I found out where the words "Crayola" and "Crayon" come from.
The word "Crayola" was originally thought up by Alice Binney. Binney, a one-time school teacher, combined the French word "craie", meaning "chalk", with "ola", shortened from the French word "oléagineux", meaning "oily". Oléagineux derives from the Latin "oleāginus", which is the adjective form of "olea", meaning more or less "olive tree".
The French "craie" comes from the Latin "creta", which also means "chalk", and, in addition, can mean "clay". Craie is also where "crayon" gets its leading "cray", though the word "crayon" existed long before Crayola crayons were invented. It first appeared around the 16th century in the French language and meant "chalk pencil" and later just shortened to "pencil", as it still means today.
Hence, given the origin of the words, "Crayola crayon" more or less just means "Oily Chalk Pencil".
Alice Binney's husband, Edwin Binney, along with his cousin, Harold Smith, founded Binney & Smith in 1885. Binney & Smith originally produced various pigments, such as chemicals used to make tires black (which drastically increases the durability of the tires over natural rubber, which is white) as well as red iron oxide pigment used in the now classic red barn paint.
In the late 1890s and early 1900s, Binney & Smith began developing product lines for schools and children to use. This began after they purchased a stone mill company and started making slate pencils for schools. With that line of product performing well, they then focused on educational products targeting specific needs in classrooms of the day, likely getting ideas from suggestions from Alice Binney who was once a school teacher.
These products included the world's first dustless chalk, called "chalk crayons", for which they won a gold medal in the 1904 St. Louis World's Fair, and, of course, the wax crayon sold under the "Crayola" brand beginning in 1903.
The wax Crayola crayon itself was simply a modified version of an industrial product Binney & Smith sold, typically used to mark crates and barrels. This original industrial wax crayon, however, was not safe for children to use as it contained certain toxic chemicals to achieve the necessary colors. They soon found ways to modify the ingredients to make them kid-safe, using non-toxic pigments, and began marketing these wax based crayons to children (with wrappers around the sticks) and to artists (without wrappers).
Today, Binney & Smith, which in turn owns Crayola, is owned by Hallmark Cards Inc., who purchased Binney & Smith in 1984.
Edwin and Alice Binney's daughter Dorothy was once married to publisher George P. Putnam, who would later marry Amelia Earhart.
The gold medal Binney & Smith won in the 1904 World's Fair is why they started putting a gold medal design on their product packages, something that they continued to do into the 1950s.
Edwin Binney and Harold Smith formed their company from Edwin's father's Peekskill Chemical Works company, which Edwin's father, Joseph Binney, retired from in 1885.
Only three Crayola crayon colors have had their original names changed in the company's history. Those were: Indian red (to chestnut) in 1998; Prussian blue (to midnight blue) in 1958; and flesh (to peach) in 1962.
In order to properly light sets on movies, carbon-arc lamps were once used. These lamps contained graphite electrodes that were called crayons.
The first "crayons" were made in Ancient Egypt, though not in the form we have today. The Egyptians combined beeswax with various colored pigments. These were then used to write and paint on stone. Once the writing or image was made on the stone, they'd use a strong heat source on the design, which would embed or "burn" it in the stone.
The first crayons resembling the modern crayon were made in Europe. They were originally made out of charcoal and oil mixed together, but the charcoal was soon replaced with various pigments in powdered form to allow for different colored crayons. Finally, they ceased using oil and used wax instead, as it was easier to work with and provided a stronger writing stick.
The 100 billionth Crayola crayon was produced in 1996 and was molded by Mr. Rogers in an episode of Mr. Rogers' Neighborhood.
The largest Crayola crayon ever made was 15 feet high, 16 inches in diameter, and weighed around 3/4 of a ton. It was created for the company's 100th anniversary.
The original colors in the first box of eight Crayola crayons were: black, brown, blue, red, purple, orange, yellow, and green. These first boxes of crayons sold for a nickel.
The largest crayon set sold by Crayola is the 832 pack, which is sold primarily to schools. The largest pack with unique crayons (based on color and additive like glitter), is the 200 pack.
Binney & Smith Inc. continued to produce industrial pigments until 1955 when they sold their Pigment Division to Columbia Carbon Company.
Oléagineux in turn gave rise to the English word oleaginous, which also means "oily".
The Crayola brand is said to have a 99% name recognition in the United States. Further, according a study done at Yale University, the smell of Crayola crayons is the 18th most recognizable scent to adult Americans. The top two most recognizable scents in that study were coffee and peanut butter.
Binney & Smith not only owns Crayola, but also owns Silly Putty, which they acquired in 1977.
The Smithsonian Institute added the Crayola crayon 64 count box to their permanent collection in 1998. Two years later, Crayola got another one of its products inducted into a Smithsonian collection, when Silly Putty was inducted into the Material World collection. One year after that, Silly Putty was inducted into the Toy Hall of Fame. The Crayola crayon was inducted into the Toy Hall of Fame in 1998.
The motivation for creating Silly Putty was to create a synthetic rubber substitute. The Allies were desperately short on rubber during WWII thanks to Japan invading various rubber producing countries in the Pacific Rim.
The first inventor of Silly Putty is up for debate, but Crayola states that James Write, working for General Electric, invented it in 1943, though there were a couple others who independently invented it around the same time period. Silly Putty didn't make a good rubber substitute and didn't appear to be good for anything else, even after Write sent samples of it to scientists all over the world to try to see if they could find any use for it. It wasn't until 1949 that a toy store owner, Ruth Fallgatter, got a hold of it and decided to sell it as a bouncing putty toy.
The name Silly Putty wasn't coined until later when Peter Hodgson, the marketing consultant that had helped Ruth Fallgatter produce her catalog, decided to sell it in the now classic plastic egg shells. At the time, he was $12,000 in debt and, given how well it had sold for Fallgatter in her catalog, figured it would do the same for him. Within three days he had sold nearly 1/4 of a million eggs of Silly Putty at $1 an egg.
Interestingly, Silly Putty dissolves in alcohol. Because of this, alcohol-based hand sanitizer is often the best way to get the putty out of hair or clothing. WD-40 also works well for this.
Among a lot of other things, Silly Putty makes a great fire starter as it burns fairly easily and slowly, as well as gets white hot.
Silly Putty was one of the things taken into lunar orbit in 1968 during the Apollo 8 mission.
Are you sure Crayola didn't just get its 'cray' directly from 'crayon'? I find it suspicious that Crayola's creator actually had 'craie' in mind when thinking up the name.


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L90 ou L-90  peut faire référence à :

 HMS Ledbury (L90), un destroyer d'escorte de la Royal Navy ;
 Infections atrophiques de la peau, d'après la classification internationale des maladies ;
 Valmet L-90 TP Redigo, un avion d'entraînement finlandais.

Voir aussi
 Sigles d'une lettre suivie de deux chiffres