Discovery of Non-Radial Pulsations in the White Dwarf Primary of a Cataclysmic Variable Star

1998 ◽

Vol 185 ◽

pp. 321-322 ◽

Cited By ~ 2

Author(s):

Brian Warner ◽

Liza Van Zyl

Keyword(s):

Surface Layer ◽

White Dwarf ◽

White Dwarfs ◽

High Probability ◽

Binary Systems ◽

Variable Star ◽

Cataclysmic Variable ◽

Instability Strip ◽

Rotation Periods ◽

Radial Pulsations

Non-radial pulsations in isolated white dwarfs have been known for 25 years and it has been shown that the hydrogen-rich (DA) white dwarfs have a high probability of pulsating if they lie in the instability strip with effective temperature between 11500 and 13200 K - the ZZ Ceti stars (e.g. Kepler and Nelan 1993). Analysing techniques developed for such stars allow derivation of masses, luminosities, rotation periods, hydrogen surface layer masses and other properties (e.g. Kepler and Bradley 1995). A number of binary systems are known in which the primary is a white dwarf; dominant in this class are the cataclysmic variable (CV) stars. Until now no CV primary has been found to have non-radial pulsations.

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The Intermediate Polars

International Astronomical Union Colloquium ◽

10.1017/s0252921100090291 ◽

1983 ◽

Vol 72 ◽

pp. 155-172

Author(s):

Brian Warner

Keyword(s):

Magnetic Fields ◽

White Dwarf ◽

Variable Star ◽

Theoretical Models ◽

Cataclysmic Variable ◽

General Role ◽

X Ray ◽

Low Mass ◽

Intermediate Polars ◽

X Ray Binaries

Until 1976, cataclysmic variable star research proceeded with few requirements for the inclusion of magnetic fields in theoretical models. Although models for low-mass X-ray binaries stressed the importance of magnetic fields (Lamb et at. 1973) and there was an increasing number of known magnetic single white dwarfs (Angel 1977), and a magnetised white dwarf had been one of the models proposed to explain the rapid oscillations in DQ Her (Herbst et al. 1974, Katz 1975), there was no anticipation of the more general role that magnetic fields now seem destined to play. The two major reviews of the time (Robinson 1976, Warner 1976) scarcely considered the presence of magnetic fields.

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Possible role of the white dwarf in grain formation in cataclysmic variable systems

Astrophysics and Space Science ◽

10.1007/bf00668123 ◽

1987 ◽

Vol 131 (1-2) ◽

pp. 443-447 ◽

Cited By ~ 5

Author(s):

J. S. Albinson ◽

A. Evans

Keyword(s):

White Dwarf ◽

Cataclysmic Variable ◽

Grain Formation

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Interacting Binary White Dwarf Stars

Symposium - International Astronomical Union ◽

10.1017/s0074180900122727 ◽

1992 ◽

Vol 151 ◽

pp. 461-464

Author(s):

J.-E. Solheim

Keyword(s):

White Dwarf ◽

Structural Changes ◽

Light Curves ◽

Physical Parameters ◽

Dwarf Stars ◽

White Dwarf Stars ◽

Test Models ◽

Radial Pulsations ◽

Whole Earth

This group of stars consists of 4 systems, also called helium cataclysmics. Three of them show photometric variations and have been studied by the Whole Earth Telescope (WET), which have revealed multiperiodic light curves showing the signature of g-mode non-radial pulsations on the accreting star. The combination of accretion and g-mode pulsations gives a unique opportunity to test models for the accreator's structural changes in response to accretion. IUE-spectra provide additional physical parameters.

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The Effective Temperature Distribution Function of Cataclysmic Variable White Dwarfs

International Astronomical Union Colloquium ◽

10.1017/s0252921100104622 ◽

1987 ◽

Vol 93 ◽

pp. 47-51

Author(s):

E.M. Sion

Keyword(s):

Distribution Function ◽

Temperature Distribution ◽

Orbital Period ◽

White Dwarf ◽

White Dwarfs ◽

Cataclysmic Variables ◽

Cataclysmic Variable ◽

Term Evolution ◽

Effective Temperatures

AbstractWith the recent detection of direct white dwarf photospheric radiation from certain cataclysmic variables in quiescent (low accretion) states, important implications and clues about the nature and long-term evolution of cataclysmic variables can emerge from an analysis of their physical properties. Detection of the underlying white dwarfs has led to a preliminary empirical CV white dwarf temperature distribution function and, in a few cases, the first detailed look at a freshly accreted while dwarf photosphere. The effective temperatures of CV white dwarfs plotted versus orbital period for each type of CV appears to reveal a tendency for the cooler white dwarf primaries to reside in the shorter period systems. Possible implications are briefly discussed.

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