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3851. Mass loss of M supergiants
ID:
ivo://CDS.VizieR/J/A+A/357/225
Title:
Mass loss of M supergiants
Short Name:
J/A+A/357/225
Date:
21 Oct 2021
Publisher:
CDS
Description:
The following tables present near-infrared photometry and millimeter observations of a sample of optical M supergiants, together with estimations of their luminosity and dust mass-loss rate. Near-infrared observations were done in February 1995 with the ESO T2.2m-IRAC1 and T3.6m-TIMMI instruments, millimeter observations were made in December 1994 with the IRAM-30m-telescope and in February 1995 with the SEST. For a description of the (N1-N3) and (JHKL) photometric system, see e.g. <GCPD/39> and <GCPD/09>, respectively.
3852. Mass-loss rates in LMC and SMC O stars
ID:
ivo://CDS.VizieR/J/MNRAS/470/3765
Title:
Mass-loss rates in LMC and SMC O stars
Short Name:
J/MNRAS/470/3765
Date:
21 Oct 2021
Publisher:
CDS
Description:
We use a combination of BVJHK and Spitzer [3.6], [5.8] and [8.0] photometry to determine infrared (IR) excesses for a sample of 58 Large Magellanic Cloud and 46 Small Magellanic Cloud O stars. This sample is ideal for determining IR excesses because the very small line-of-sight reddening minimizes uncertainties due to extinction corrections. We use the core-halo model developed by Lamers & Waters to translate the excesses into mass-loss rates and demonstrate that the results of this simple model agree with the more sophisticated CMFGEN models to within a factor of 2. Taken at face value, the derived mass-loss rates are larger than those predicted by Vink et al. (2001A&A...369..574V), and the magnitude of the disagreement increases with decreasing luminosity. However, the IR excesses need not imply large mass-loss rates. Instead, we argue that they probably indicate that the outer atmospheres of O stars contain complex structures and that their winds are launched with much smaller velocity gradients than normally assumed. If this is the case, it could affect the theoretical and observational interpretations of the 'weak wind' problem, where classical mass-loss indicators suggest that the mass-loss rates of lower luminosity O stars are far less than expected.
3853. Mass-loss return from LMC evolved stars. VI.
ID:
ivo://CDS.VizieR/J/ApJ/753/71
Title:
Mass-loss return from LMC evolved stars. VI.
Short Name:
J/ApJ/753/71
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present results from the first application of the Grid of Red Supergiant and Asymptotic Giant Branch ModelS (GRAMS) model grid to the entire evolved stellar population of the Large Magellanic Cloud (LMC). GRAMS is a pre-computed grid of 80843 radiative transfer models of evolved stars and circumstellar dust shells composed of either silicate or carbonaceous dust. We fit GRAMS models to ~30000 asymptotic giant branch (AGB) and red supergiant (RSG) stars in the LMC, using 12 bands of photometry from the optical to the mid-infrared. Our published data set consists of thousands of evolved stars with individually determined evolutionary parameters such as luminosity and mass-loss rate. The GRAMS grid has a greater than 80% accuracy rate discriminating between oxygen- and carbon-rich chemistry.
3854. Mass-luminosity relation
ID:
ivo://CDS.VizieR/J/AJ/106/773
Title:
Mass-luminosity relation
Short Name:
J/AJ/106/773
Date:
21 Oct 2021
Publisher:
CDS
Description:
Mass-luminosity relations determined at infrared wavelengths are presented for stars with masses 1.0 to 0.08 solar masses. Using infrared speckle imaging techniques on a sample of nearby binaries, we have been able to concentrate on the lower main sequence (Mass<=0.5M_sun_), for which an accurate mass-luminosity calibration has remained problematic. In addition, the mass-visual luminosity relation for stars with 2.0>=Mass>=0.08M_sun_ is produced by implementing new photometric relations linking V to JHK wavelengths for the nearby stars, supplemented with eclipsing binary information. These relations predict that objects with masses ~0.08 solar masses have M(K)~=10 and M(V)~=18.
3855. 2MASS M-dwarf discoveries
ID:
ivo://CDS.VizieR/J/ApJ/476/311
Title:
2MASS M-dwarf discoveries
Short Name:
J/ApJ/476/311
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have obtained follow-up spectroscopy of eight late dwarf candidates discovered in a 105deg^2^ area observed with the 2MASS (2 Micron All-Sky Survey) Prototype Camera during test runs between 1992 and 1994. These objects were chosen because of their red infrared colors (e.g., J-Ks>=1.10) and/or red OIR colors (e.g., R-Ks>=6.00). All eight are late M dwarfs, six of which have spectral types later than van Biesbroeck 8 (type M7 V). Despite the fact that we have only followed up a fraction of the reddest sources discovered, the number of known M dwarfs of type M7 and cooler has been increased by 30%. Extrapolation of these results alone shows that over 2000 dwarfs of similar spectral type and with Ks<=14.0 will be imaged by 2MASS over the entire sky. One of these new discoveries is astonishingly cool and has a tentative type of >=M10V. This dwarf, one of the least luminous objects yet discovered, could itself be a high-mass brown dwarf, thus providing another empirical data point in a regime where few such objects are now recognized. Only the substellar suspect GD 165 B and the bona fide brown dwarf GL 229 B, both discovered as companions to known stars, are cooler. Thus, this 2MASS discovery becomes the coolest isolated object so far identified.
3856. 2MASS observation of BL Lac objects
ID:
ivo://CDS.VizieR/J/other/NewA/11.27
Title:
2MASS observation of BL Lac objects
Short Name:
J/other/NewA/11.
Date:
21 Oct 2021
Publisher:
CDS
Description:
The 2MASS observations of known BL Lac objects are presented in this paper. The 2MASS associations for 511 BL Lac objects are identified. From the 2MASS near infrared two-color diagram it is seen that majority (about 70%) of objects are lying alone with or very close to the power law distribution implying that there is no need to invoke any significant radiation mechanism additional to a power law continuum for those sources. However, many sources (about 30%) are still located very close to the blackbody distribution indicative of the possible contributions from the host galaxies. In addition, the average spectral index derived for the near infrared region is 0.66+/-0.34 that is rather smaller than that from the previous results indicative of the possible influence from the host galaxies and/or from the lack or weakness of the radio emissions from most sources newly discovered by recent X-ray missions.
3857. 2MASS observations of Be stars
ID:
ivo://CDS.VizieR/J/other/NewA/10.325
Title:
2MASS observations of Be stars
Short Name:
J/other/NewA/10.
Date:
21 Oct 2021
Publisher:
CDS
Description:
A catalogue of almost all known Galactic Be stars in the 2MASS (<II/246>) database (1185 in total) and in the MSX (<V/114>) database (225 in total) is presented in this paper. From the color-color diagrams and spectral indexes, it is found that the IR excesses for many samples are due to free-free and free-bound emission from the ionized material around a Be star as suggested previously and that the mean spectral index derived for the samples is 1.50+/-0.34 between J to K bands and 1.14+/-0.42 between K to A bands, respectively. However, it is also found that there are eight Be stars that have large near infrared excess emission with spectral index values outside the range expected for freefree and freebound emission. This is likely attributed to circumstellar dust emission.
3858. 2MASS observations of IRAS 1Jy ULIRGs
ID:
ivo://CDS.VizieR/J/AJ/131/1942
Title:
2MASS observations of IRAS 1Jy ULIRGs
Short Name:
J/AJ/131/1942
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Two Micron All Sky Survey observation of the IRAS 1Jy sample of ultraluminous infrared galaxies (ULIRGs) is presented in this paper. Together with the IRAS photometric data, the properties and energy sources of the IRAS 1Jy sample of ULIRGs in the near- and far-infrared are discussed.
3859. 2MASS photometry of cataclysmic variables
ID:
ivo://CDS.VizieR/J/other/NewA/13.133
Title:
2MASS photometry of cataclysmic variables
Short Name:
J/other/NewA/13.
Date:
21 Oct 2021
Publisher:
CDS
Description:
Spatial distribution, galactic model parameters and luminosity function of cataclysmic variables (CVs) in the solar neighbourhood have been found using distances estimated from the period-luminosity-colours (PLCs) relation of CVs. It can be concluded that exponential function fits better to the observational z-distributions of the whole CVs in the sample, non-magnetic CVs and dwarf novae, while the sech^2^ function is more appropriate for nova-like stars and polars. The vertical scaleheight of CVs is 158+/-14pc for the 2MASS J band limiting apparent magnitude of 15.8. The discrepancies between the theoretical and observational population studies of CVs can be at least partly removed if the sech^2^ density function is used in deriving the galactic model parameters. We estimated the vertical scaleheights of 128+/-20pc and 160+/-5pc for dwarf novae and nova-like stars, respectively. The local space density of CVs is found ~3x10^-5^pc^-3^ which is in agreement with the lower limit of the theoretical predictions. The luminosity function of CVs shows a trend toward higher space density at low luminosity, implying an increase in the number of short-period systems.
3860. 2MASS photometry of hot subdwarf stars
ID:
ivo://CDS.VizieR/J/AJ/126/1455
Title:
2MASS photometry of hot subdwarf stars
Short Name:
J/AJ/126/1455
Date:
21 Oct 2021
Publisher:
CDS
Description:
Utilizing the Two Micron All Sky Survey (2MASS) Second Incremental Data Release Catalog, we have retrieved near-IR magnitudes for several hundred hot subdwarfs (sdO and sdB stars) drawn from the Catalogue of Spectroscopically Identified Hot Subdwarfs by Kilkenny et al. (1988SAAOC..12....1K). This sample size greatly exceeds that of previous studies of hot subdwarfs. Examining 2MASS photometry alone or in combination with visual photometry (Johnson BV or Stroemgren uvby) available in the literature, we show that it is possible to identify hot subdwarf stars that exhibit atypically red IR colors, which can be attributed to the presence of an unresolved late-type companion. Utilizing this large sample, we attempt for the first time to define an approximately volume-limited sample of hot subdwarfs. We discuss the considerations, biases, and difficulties in defining such a sample. We find that, of the hot subdwarfs in Kilkenny et al. (1988SAAOC..12....1K), about 40% in a magnitude-limited sample have colors that are consistent with the presence of an unresolved late-type companion. Binary stars are overrepresented in a magnitude-limited sample. In an approximately volume-limited sample the fraction of composite-color binaries is about 30%.