2002ApJ...572..456S -
Astrophys. J., 572, 456-460 (2002/June-2)
The extraordinary cataclysmic binary RU Pegasi: the hottest white dwarf in a dwarf nova.
SION E.M. and URBAN J.
Abstract (from CDS):
We present the results of the first multicomponent synthetic spectral analysis of International Ultraviolet Explorer (IUE) archival spectra of the long-period dwarf nova RU Peg during quiescence. The best-fit, high-gravity, solar composition photosphere models yield Teff=50,000-53,000 K with scale factor distances of 250 pc. Optically thick accretion disk models imply accretion rates between 1x10–9 and 1x10–10M☉ yr–1 in order to match the steeply sloping far-UV continuum. However, the best-fit accretion disk models yield distances from 600 to 1300 pc, well beyond the estimated distance range of 130-300 pc. Using rough theoretical flux arguments and the distance estimates, we find better agreement between the observed far-UV luminosity and the predicted far-UV luminosity of a hot, massive, white dwarf model than with an accretion disk model. RU Peg appears to contain the hottest white dwarf yet found in a dwarf nova. We cannot rule out that the far-UV energy distribution is due to a multitemperature white dwarf with cooler, more slowly rotating higher latitudes and a rapidly spinning, hotter equatorial belt. We discuss implications of our analysis for theoretical predictions of the disk instability theory of dwarf nova outbursts. We discuss a comparison between RU Peg's white dwarf and the observed properties of other analyzed white dwarfs in dwarf novae.
Abstract Copyright:
∼
Journal keyword(s):
Accretion, Accretion Disks - Stars: Binaries: Close - Stars: Dwarf Novae - Stars: Individual: Constellation Name: RU Pegasi - Stars: White Dwarfs
Simbad objects:
8
Full paper
View the references in ADS
To bookmark this query, right click on this link: simbad:2002ApJ...572..456S and select 'bookmark this link' or equivalent in the popup menu