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Instability of g-Mode Oscillations in White Dwarf Stars

Published online by Cambridge University Press:  12 April 2016

Douglas A. Keeley
Douglas A. Keeley*
Affiliation:
Science Applications, Inc., 5 Palo Alto Square, Suite 200, Palo Alto CA 94304

Abstract

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A white dwarf model with M=.6 M⊙, Te=12000K, and L=1.2×1031 erg sec-1 provided by A.N. Cox has been tested for linear stability of radial oscillations. The radial mode instability first reported for this model by Cox, et. al (1979) has been confirmed. The growth rates obtained are comparable to the rates found by Cox. A sequence of ℓ=2 g-modes has also been found to be unstable. The e-folding times range from around 1011 periods for a 137 second mode (1 radial node) to less than 100 periods for a 629 second mode (17 nodes). It is likely that the latter rate is too high because the eigenfunction has been forced to vanish at the non-zero inner radius of the model, at which the Brunt-Väisäla frequency is barely less than the mode frequency.

Type
Colloquium Session VI
Information
International Astronomical Union Colloquium , Volume 53: White Dwarfs and Variable Degenerate Stars , August 1979 , pp. 388 - 391
Copyright
Copyright © The University of Rochester 1979

References

Cox, A.N., Hodson, S.W., and Starrfield, S.G., 1979, Proceedings of the Non-radial and Non-linear Stellar Pulsation Workshop, Tucson, Arizona, 12-16 March.Google Scholar
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Keeley, D., 1979, Proceedings of the Non-radial and Non-Linear Stellar Pulsation Workshop, University of Arizona, Tucson, Arizona, March 12-16.Google Scholar
Van Horn, H.M., 1979, Physics Today, Volume 32, #1, p. 23, January.Google Scholar