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We present new calculations for the Stark broadening of the hydrogen line profiles in the dense atmospheres of white dwarf stars. Our improved model is based on the unified theory of Stark broadening from Vidal, Cooper & Smith, but it also…

太阳与恒星天体物理 · 物理学 2009-07-22 P. -E. Tremblay , P. Bergeron , J. Dupuis

We present a series of systematic abundance measurements for 89 hydrogen atmosphere (DA-type) white dwarfs with temperatures spanning 16000-77000K drawn from the FUSE spectral archive. This is the largest study to date of white dwarfs where…

太阳与恒星天体物理 · 物理学 2015-06-18 M. A. Barstow , J. K. Barstow , S. L. Casewell , J. B. Holberg , I. Hubeny

White dwarf evolution is essentially a gravothermal cooling process, which,for cool white dwarfs, sensitively depends on the treatment of the outer boundary conditions. We provide detailed outer boundary conditions appropriate for computing…

太阳与恒星天体物理 · 物理学 2015-06-11 R. D. Rohrmann , L. G. Althaus , E. García-Berro , A. H. Córsico , M. M. Miller Bertolami

We present a spectroscopically identified catalogue of 72 DA white dwarfs from the LAMOST pilot survey. 35 are found to be new identifications after cross-correlation with the Eisenstein et al. and Villanova catalogues. The effective…

太阳与恒星天体物理 · 物理学 2015-06-15 J. K. Zhao , A. L. Luo , T. D. Oswalt , G. Zhao

We present an experimental platform for measuring hydrogen Balmer emission and absorption line profiles for plasmas with white dwarf (WD) photospheric conditions (T_e ~ 1 eV, n_e ~ 10^17 cm^-3). These profiles will be used to benchmark WD…

We present the first grid of mean three-dimensional (3D) spectra for pure-hydrogen (DA) white dwarfs based on 3D model atmospheres. We use CO5BOLD radiation-hydrodynamics 3D simulations instead of the mixing-length theory for the treatment…

太阳与恒星天体物理 · 物理学 2015-06-17 P. -E. Tremblay , H. -G. Ludwig , M. Steffen , B. Freytag

Results are presented from the first detailed spectroscopic observations of the recently identified intermediate polar RXJ0028.8+5917/V709 Cas. The study of the emission line radial velocities allows us to remove the uncertainties on the…

天体物理学 · 物理学 2009-11-06 J. M. Bonnet-Bidaud , M. Mouchet , D. de Martino , G. Matt , C. Motch

Balmer lines are an important diagnostic of stellar atmospheric structure, since they are formed at a wide range of depths within the atmosphere. The different Balmer lines are formed at slightly different depths making them useful…

天体物理学 · 物理学 2007-05-23 B. Smalley , F. Kupka

White dwarf photospheric parameters are usually obtained by means of spectroscopic or photometric analysis. These results are not always consistent with each other, with the published values often including just the statistical…

We computed Doppler beaming factors for DA, DB, and DBA white dwarf models, as well as for main sequence and giant stars covering the transmission curves of the Sloan, UBVRI, HiPERCAM, Kepler, TESS, and Gaia photometric systems. The…

太阳与恒星天体物理 · 物理学 2020-09-30 A. Claret , E. Cukanovaite , K. Burdge , P. -E. Tremblay , S. Parsons , T. R. Marsh

We rediscuss the temperature of O dwarfs based on new non-LTE line blanketed atmosphere models including stellar winds computed with the CMFGEN code of Hillier & Miller (1998). Compared to the latest calibration of Vacca et al. (1996), the…

天体物理学 · 物理学 2010-04-29 F. Martins , D. Schaerer , D. J. Hillier

We perform a study of 62 solar analog stars to compute their effective temperatures (Teff) using the Balmer line wing fitting procedure and compare them with Teff values obtained using other commonly employed methods. We use observed…

太阳与恒星天体物理 · 物理学 2012-06-06 D. Cornejo , I. Ramirez , P. S. Barklem

By introducing a simplified transport model of outer layers of white dwarfs we derive an analytical semi-empirical relation which constrains effective temperature-mass-radius for white dwarfs. This relation is used to classify recent data…

太阳与恒星天体物理 · 物理学 2017-01-10 Elvis do A. Soares

We present a detailed spectroscopic and photometric analysis of DA and DB white dwarfs drawn from the Sloan Digital Sky Survey with trigonometric parallax measurements available from the Gaia mission. The temperature and mass scales…

太阳与恒星天体物理 · 物理学 2019-01-08 C. Genest-Beaulieu , P. Bergeron

We report early FUSE observations of the very hot DA white dwarfs PG1342+444 and REJ0558-371. Detection of photospheric absorption lines allows us to estimate the abundances of C, O, Si, P, S and Fe, the first measurements reported for DA…

天体物理学 · 物理学 2007-05-23 M. A. Barstow , M. R. Burleigh , N. P. Bannister , J. B. Holberg , I. Hubeny

Cooling ages of white dwarfs are routinely determined by mapping effective temperatures and masses to ages using evolutionary models. Typically, the reported uncertainties on cooling ages only consider the error propagation of the…

太阳与恒星天体物理 · 物理学 2025-03-12 Praneet Pathak , Simon Blouin , Falk Herwig

We present a detailed analysis of 108 helium-line (DB) white dwarfs based on model atmosphere fits to high signal-to-noise optical spectroscopy. We derive a mean mass of 0.67 Mo for our sample, with a dispersion of only 0.09 Mo. White…

In this paper, we present corrections to the spectroscopic parameters of DB and DBA white dwarfs with -10.0 < log(H/He) < -2.0, 7.5 < log(g) < 9.0 and 12000 K < T_eff < 34000 K, based on 282 3D atmospheric models calculated with the CO5BOLD…

太阳与恒星天体物理 · 物理学 2020-11-26 Elena Cukanovaite , Pier-Emmanuel Tremblay , Pierre Bergeron , Bernd Freytag , Hans-Günter Ludwig , Matthias Steffen

Spectrophotometric observations at high signal-to-noise ratio were obtained of a complete sample of 347 DA white dwarfs from the Palomar Green (PG) Survey. Fits of observed Balmer lines to synthetic spectra calculated from pure-hydrogen…

天体物理学 · 物理学 2009-09-17 J. Liebert , P. Bergeron , J. B Holberg

Lithium abundances in a sample of halo dwarfs have been redetermined by using the new T$_{eff}$ derived by Fuhrmann et al (1994) from modelling of the Balmer lines. These T$_{eff}$ are reddening independent, homogeneous and of higher…

天体物理学 · 物理学 2007-05-23 P. Molaro , F. Primas , P. Bonifacio