Asteroseismology of white dwarf stars. I - Adiabatic results

Journal Article · Fri Feb 01 00:00:00 EST 1991 · Astrophysical Journal, Supplement Series; (United States)

DOI:https://doi.org/10.1086/191539· OSTI ID:5666930

Bradley, P A; Winget, D E ^[1]

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1. Texas, University (USA) McDonald Observatory, Austin (USA)

A preliminary investigation of the asteroseismological properties of chemically stratified evolutionary DA and DB white dwarf models is reported. The period and kinetic energy distributions for nonradial g-modes of spherical harmonic indices l = 1-3 are computed in the adiabatic approximation, and the effects of varying the total stellar masss and the surface layer masses on the pulsation properties are studied using an extensive grid of models. Significant resonant mode trapping due to chemical stratification is found. Modes trapped in the outer layers have much lower kinetic energies; these minima also show up as minima in the period spacing between modes of consecutive radial overtone k. Mode trapping occurs at the same or nearly the same value of k for different l-values. Thus, l-values of trapped modes may be identified on the basis of their period ratios. It is shown that observational identification of these period ratios can be used to constrain the mass of the star and its surface layer. 68 refs.

• OSTI ID: 5666930
• Journal Information: Astrophysical Journal, Supplement Series; (United States), Vol. 75; ISSN 0067-0049
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
WHITE DWARF STARS
STAR MODELS
ADIABATIC PROCESSES
KINETIC ENERGY
MASS
OSCILLATIONS
STAR EVOLUTION
VARIABLE STARS
DWARF STARS
ENERGY
MATHEMATICAL MODELS
STARS
640102* - Astrophysics & Cosmology- Stars & Quasi-Stellar
Radio & X-Ray Sources