The Atmospheres of White Dwarfs -- III: The Line Spectra
نویسندگان
چکیده
منابع مشابه
Two white dwarfs with oxygen-rich atmospheres.
Stars with masses ranging from 7 to 10 times the mass of the Sun end their lives either as massive white dwarfs or weak type II supernovae, but there are only limited observational constraints on either evolutionary channel. Here we report the detection of two white dwarfs with large photospheric oxygen abundances, implying that they are bare oxygen-neon cores and that they may have descended f...
متن کاملRotation velocities of white dwarfs III. DA stars with convective atmospheres
The sharp Hα NLTE line cores of hydrogen-rich (DA) white dwarfs allow their projected rotational velocities to be determined. High resolution optical spectra of 22 stars obtained with the Keck I telescope are matched by synthetic spectra computed from a grid of NLTE model atmospheres. In this paper, the third in a series on white dwarf rotation, we concentrate preferentially on DA white dwarfs ...
متن کاملRotation Velocities of DA White Dwarfs with Convective Atmospheres
The sharp Hα NLTE line cores of hydrogen rich (DA) white dwarfs allow their projected rotational velocities to be determined. High resolution optical spectra of 22 stars obtained with the Keck I telescope are matched by synthetic spectra computed from a grid of NLTE model atmospheres. We concentrate preferentially on hydrogen-rich white dwarfs with convective atmospheres, i.e. with Teff < 14 00...
متن کاملThe First Mid-Infrared Spectra of Cool White Dwarfs
We present the first mid-infrared spectra of two cool white dwarfs obtained with the Spitzer Space Telescope. We also present 3:5Y8 m photometry for 19 cool white dwarfs with 5000 K TeA 9000 K. We perform a detailed model atmosphere analysis of these white dwarfs by fitting their UBVRIJHK and Spitzer photometry with state-ofthe-art model atmospheres, and demonstrate that the optical and infrare...
متن کاملCombination Frequencies in the Fourier Spectra of White Dwarfs
Combination frequencies are observed in the Fourier spectra of pulsating DA and DB white dwarfs. They appear at sums and differences of frequencies associated with the stellar gravity-modes. Brickhill (1992) proposed that the combination frequencies result from mixing of the eigenmode signals as the surface convection zone varying in depth when undergoing pulsation. This depth changes cause tim...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Monthly Notices of the Royal Astronomical Society
سال: 1971
ISSN: 0035-8711,1365-2966
DOI: 10.1093/mnras/152.1.47