Rotation velocities of white dwarfs determined from the Ca II K line
نویسندگان
چکیده
منابع مشابه
Rotation velocities of white dwarfs determined from the Ca II K line
We determine projected rotation velocities v sin i in DAZ white dwarfs, for the first time using the rotational broadening of the Ca II K line. The results confirm previous findings that white dwarfs are very slow rotators, and set even more stringent upper limits of typically less than 10 km s−1. The few exceptions include 3 stars known or suspected to be variable ZZ Ceti stars, where the line...
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 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 white dwarf stars ?
The narrow Hα line cores observed with the Keck high resolution spectrograph of thirteen hydrogen-rich (DA) white dwarfs are analysed using line blanketed Non-LTE model atmospheres. The synthetic line profiles reproduce the observed line cores very well. Hence no evidence for additional line broadening due to rotation or to magnetic fields can be found. Statistical upper limits to the projected...
متن کاملSearch for rotation in white dwarfs
We report high-resolution spectroscopic observations of the NLTE Hα core in 28 DA white dwarfs. From a comparison with theoretically broadened NLTE models projected rotation velocities can be determined. The majority of objects are found to be compatible with zero or very small rotation with typical upper limits for v sin i of 15 km/s, corresponding to periods of hours or longer. The implicatio...
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: Astronomy & Astrophysics
سال: 2005
ISSN: 0004-6361,1432-0746
DOI: 10.1051/0004-6361:20053340