Department of Physics and Astronomy: Publications and Other Research

 

Document Type

Article

Date of this Version

3-1970

Citation

Astrophysical Journal (March 1970) 159

Comments

Copyright 1970, University of Chicago. Used by permission

Abstract

The effects of thermal imbalance (dS1/dt ≠ 0) on stellar pulsational stability have largely been ignored in the literature. Here we have used the linear, quasi-adiabatic pulsation theory to make a preliminary investigation of such effects. Analyses of the standard model and of a white dwarf show that, for these cases, "ordinary" terms in the stability integrals greatly outweigh the "extra" terms considered here. The latter become more important when substantial ionization zones exist in the stellar matter. It is argued that the influence of thermal imbalance on pulsational stability should be quite small for stars crossing the H-R diagram in early post-main-sequence evolution, and for cooling degenerate stars. On the other hand, during pre-main-sequence contraction the thermal-imbalance terms are more likely to be important, and for thermal runaways in shell-burning stars these terms are almost certainly crucial.

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