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J/A+A/615/A78       Spectral models for binary products      (Goetberg+, 2018)

Spectral models for binary products: Unifying Subdwarfs and Wolf-Rayet stars as a sequence of stripped-envelope stars. Goetberg Y., de Mink S.E., Groh J.H., Kupfer T., Crowther P.A., Zapartas E., Renzo M. <Astron. Astrophys. 615, A78 (2018)> =2018A&A...615A..78G (SIMBAD/NED BibCode)
ADC_Keywords: Models ; Stars, atmospheres ; Stars, Wolf-Rayet ; Stars, subdwarf ; Energy distributions Keywords: binaries: close - stars: atmospheres - subdwarfs - stars: Wolf-Rayet - galaxies: stellar content - ultraviolet: galaxies Abstract: Stars stripped of their hydrogen-rich envelope through interaction with a binary companion are generally not considered when accounting for ionizing radiation from stellar populations, despite the expectation that stripped stars emit hard ionizing radiation, form frequently, and live 10-100 times longer than single massive stars. We compute the first grid of evolutionary and spectral models specially made for stars stripped in binaries for a range of progenitor masses (2-20M) and metallicities ranging from solar to values representative for pop II stars. For stripped stars with masses in the range 0.3-7M, we find consistently high effective temperatures (20000-100000K, increasing with mass), small radii (0.2-1R), and high bolometric luminosities, comparable to that of their progenitor before stripping. The spectra show a continuous sequence that naturally bridges subdwarf-type stars at the low-mass end and Wolf-Rayet-like spectra at the high-mass end. For intermediate masses we find hybrid spectral classes showing a mixture of absorption and emission lines. These appear for stars with mass-loss rates of 10-8-10-6M/yr, which have semi-transparent atmospheres. At low metallicity, substantial hydrogen-rich layers are left at the surface and we predict spectra that resemble O-type stars instead. We obtain spectra undistinguishable from subdwarfs for stripped stars with masses up to 1.7M, which questions whether the widely adopted canonical value of 0.47M is uniformly valid. Only a handful of stripped stars of intermediate mass have currently been identified observationally. Increasing this sample will provide necessary tests for the physics of interaction, internal mixing, and stellar winds. We use our model spectra to investigate the feasibility to detect stripped stars next to an optically bright companion and recommend systematic searches for their UV excess and possible emission lines, most notably HeII λ4686 in the optical and HeII λ1640 in the UV. Our models are publicly available for further investigations or inclusion in spectral synthesis simulations. Description: We have modeled the spectra of stars stripped of their envelope through mass transfer in binary systems using the non-LTE radiative transfer code CMFGEN. These stripped stars span a mass range from 0.34 up to 7.9M. We present four metallicities; Z=0.014 (solar), 0.006, 0.002, and 0.0002. For each model we provide the spectral energy distribution and the normalized spectrum. We also provide the magnitudes for the following filters: GALEX/NUV, GALEX/FUV Swift/UVW1, Swift/UVW2, Swift/UVM2, Johnson UBVRI, 2MASS/J, 2MASS/H, and 2MASS/Ks. These magnitudes are presented in tables for each metallicity grid. Each model is labelled in the following way: M1Xq0.8PXZXvinf1.5, where X stands for initial mass (mass of the star before stripping), initial period, and metallicity, in order. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file m0002.dat 258 23 Absolute magnitudes of the spectral models of stripped stars in the grid grid_0002, Z=0.0002 grid_0002/* 0 23 Individual spectra and SED for each model m002.dat 258 23 Absolute magnitudes of the spectral models of stripped stars in the grid grid_002, Z=0.002 grid_002/* 0 23 Individual spectra and SED for each model m006.dat 258 23 Absolute magnitudes of the spectral models of stripped stars in the grid grid_006, Z=0.006 grid_006/* 0 23 Individual spectra and SED for each model m014.dat 258 23 Absolute magnitudes of the spectral models of stripped stars in the grid grid_014, Z=0.014 grid_014/* 0 23 Individual spectra and SED for each model
Byte-by-byte Description of file (# headlines): m0002.dat m002.dat m006.dat m014.dat
Bytes Format Units Label Explanations
1- 32 A32 --- Model Model name (1) 34- 49 F16.13 mag NUV NUV absolute magnitude of the spectral model 51- 66 F16.13 mag FUV FUV absolute magnitude of the spectral model 68- 83 F16.13 mag UVW1 UVW1 absolute magnitude of the spectral model 85-101 F17.13 mag UVW2 UVW2 absolute magnitude of the spectral model 103-119 F17.14 mag UVM2 UVM2 absolute magnitude of the spectral model 121-137 F17.14 mag U U absolute magnitude of the spectral model 139-154 F16.13 mag B B absolute magnitude of the spectral model 156-171 F16.13 mag V V absolute magnitude of the spectral model 173-189 F17.14 mag R R absolute magnitude of the spectral model 191-206 F16.13 mag I I absolute magnitude of the spectral model 208-223 F16.13 mag J J absolute magnitude of the spectral model 225-240 F16.13 mag H H absolute magnitude of the spectral model 242-258 F17.14 mag Ks Ks absolute magnitude of the spectral model
Note (1): Model name is subdirectory grid_0002 for m0002.dat, grid_002 for m002.dat, grid_006 for m006.dat and grid_014 for m014.dat.
Acknowledgements: Ylva Gotberg, y.l.l.gotberg(at)uva.nl
(End) Patricia Vannier [CDS] 26-Mar-2018
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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