Publication Abstracts

Stothers 1999

Stothers, R.B., 1999: Criterion for the dynamical stability of a non-adiabatic spherical self-gravitating body. Mon. Not. Roy. Astron. Soc., 305, 365-372, doi:10.1046/j.1365-8711.1999.02444.x.

Why do stars and planets maintain their dynamical stability over cosmically long periods of time? The standard answer is that the first generalized adiabatic exponent of their material, Γ1, exceeds the value 4/3. Yet it has never been rigorously demonstrated (except for the simple one-zone model) that non-adiabatic effects do not modify this result at some level. Many authors, in fact, have suggested the probable need for a non-adiabatic correction to the square of the radial adiabatic eigenfrequency, σ2, which ostensibly governs dynamical stability in the more general case where Γ1 varies throughout a fully distributed self-gravitating spherical body. Here, a carefully controlled series of numerical experiments based on linear and non-linear hydrodynamical models of highly non-adiabatic spherically symmetric stellar envelopes (mimicking the envelopes of luminous blue variables) confirms, quite generally, that the purely adiabatic criterion σ2 > 0 does in fact determine dynamical stability. An accurate approximation to this criterion is further shown to be that the volumetric pressure-weighted average of Γ1 must exceed 4/3. These results, which concern only radial stability, verify the theoretical basis of the more sophisticated models for luminous blue variables that were constructed by the author and C.-W. Chin, but they do not support the objections to these models raised by W. Glatzel and M. Kiriakidis.

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BibTeX Citation

  author={Stothers, R. B.},
  title={Criterion for the dynamical stability of a non-adiabatic spherical self-gravitating body},
  journal={Monthly Notices of the Royal Astronomical Society},

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RIS Citation

ID  - st02200i
AU  - Stothers, R. B.
PY  - 1999
TI  - Criterion for the dynamical stability of a non-adiabatic spherical self-gravitating body
JA  - Mon. Not. Roy. Astron. Soc.
JO  - Monthly Notices of the Royal Astronomical Society
VL  - 305
SP  - 365
EP  - 372
DO  - 10.1046/j.1365-8711.1999.02444.x
ER  -

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