منابع مشابه
Synthetic spectra of massive stars as tool for the spectral analysis of stars and stellar clusters
We present fully consistent models for O-type stars that re-produce the observed UV spectra simultaneously with the observed ter-minal velocities and mass loss rates. We demonstrate how, as a conse-quence, the models can be used to determine the stellar parameters fromthe observed UV spectra alone. 1. Comparison with observations For a detailed description of the treatment of no...
متن کاملImproved synthetic spectra of helium-core white dwarf stars
We examine the emergent fluxes from helium-core white dwarfs following their evolution from the end of pre-white dwarf stages down to advanced cooling stages. For this purpose, we include a detailed treatment of the physics of the atmosphere, particularly an improved representation of the state of the gas by taking into account non-ideal effects according to the so-called occupation probability...
متن کاملWN stars in the LMC: Parameters and atmospheric abundances
The spectra of 18 WN stars in the Large Magellanic Cloud (LMC) are quantitatively analyzed by means of “standard” Wolf-Rayet model atmospheres, using the helium and nitrogen lines as well as the spectral energy distribution. The hydrogen abundance is also determined. Carbon is included for a subset of 4 stars. The studied sample covers all spectral subtypes (WN2... WN9) and also includes one WN...
متن کاملPopulations of WC and WN stars in Wolf-Rayet galaxies
We report the detection of WC stars in five WolfRayet (W-R) galaxies: He 2-10, NGC 3049, NGC 3125, NGC 5253 and Tol 89. The faint broad C IV λ5808 line requires sufficiently high S/N (>∼ 40) to be detected explaining the nondetection of this WC feature in previous observations. From the measurement of W-R emission lines (N III λ4640+C III λ4650, He II λ4686, and C IV λ5808), we conclude that al...
متن کاملThe nitrogen spectra of Wolf-Rayet stars A grid of models and its application to the Galactic WN sample
Adopting the “standard model” for Wolf-Rayet atmospheres, non-LTE radiation transfer calculations are performed which account for helium and nitrogen. Grids of theoretical models are presented for the whole relevant parameter range. The WN classification criteria are employed in order to identify the subtype domains, and inconsistencies are discussed. The (almost complete) sample of known Galac...
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ژورنال
عنوان ژورنال: Symposium - International Astronomical Union
سال: 1982
ISSN: 0074-1809
DOI: 10.1017/s0074180900028813