A NEW SMALL-AMPLITUDE VARIABLE HOT DQ WHITE DWARF
نویسندگان
چکیده
منابع مشابه
Hot DQ White Dwarf Stars: A New Challenge to Stellar Evolution
We report the discovery of a new class of hydrogen-deficient stars: white dwarfs with an atmosphere primarily composed of carbon, with little or no trace of hydrogen or helium. Our analysis shows that the atmospheric parameters found for these stars do not fit satisfactorily in any of the currently known theories of post-asymptotic giant branch (AGB) evolution, although these objects might be t...
متن کاملHST Spectra of GW Librae: A Hot Pulsating White Dwarf in a Cataclysmic Variable
We have obtained Hubble Space Telescope UV spectra of the white dwarf in GW Lib, the only known non-radially pulsating white dwarf in a cataclysmic variable, and the first known DAZQ variable. The UV light curve reveals large amplitude (10%) pulsations in the UV with the same periods (646, 376 and 237 s) as those seen at optical wavelengths, but the mean spectrum fits with an average white dwar...
متن کاملSearch for Oxygen in Cool Dq White Dwarf Atmospheres
The existence of carbon in cool He white dwarf (WD) atmospheres has been known for a relatively long time[5]. The presence of carbon in these atmospheres is explained by convective dredge up of interior carbon [6]. Pelletier et al. (1986) presented the first detailed calculations of this process and showed that carbon diffuses upwards from the core into the base of the He-rich envelope where it...
متن کاملHot DAVs: a probable new class of pulsating white dwarf stars
We have discovered a pulsating DA white dwarf at the lower end of the temperature range 45 000–30 000 K where a few helium atmosphere white dwarfs are known. There are now three such pulsators known, suggesting that a new class of theoretically predicted pulsating white dwarf stars exists. We name them the hot DAV stars. From high-speed photometric observations with the ULTRACAM photometer on t...
متن کاملHot White Dwarf Donors in Ultracompact X-ray Binaries
The discovery of two accreting millisecond X-ray pulsars in binaries with ≈ 43 minute orbital periods allows for a new probe of the donor’s structure. For XTE J1751-305, only a hot white dwarf (WD) can fill the Roche Lobe. A cold He WD is a possible solution for XTE J0929-314, though I will show that evolutionary arguments make a hot WD more likely. In addition to being larger than the T = 0 mo...
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: The Astrophysical Journal
سال: 2010
ISSN: 2041-8205,2041-8213
DOI: 10.1088/2041-8205/720/2/l159