Publication Abstracts

Stothers and Chin 1973

Stothers, R., and C.-W. Chin, 1973: Stellar evolution at high mass based on the Ledoux criterion for convection. Astrophys. J., 179, 555-568, doi:10.1086/151895.

Theoretical evolutionary sequences of models for stars of 15 and 30 M have been computed from the zero-age main sequence to the end of core helium burning, with the use of the Ledoux criterion for convective instability. The sensitivity of the models to the most important physical input parameters has been tested. During the earliest stages of core helium depletion, the envelope rapidly expands into the red-supergiant configuration because the hydrogen profile in the intermediate zone remains essentially unaltered by local convection. At 15 M, a blue loop on the H-R diagram ensues if the initial metals abundance, initial helium abundance, or 12C + α reaction rate is sufficiently large, or if the 3α reaction rate is sufficiently small. These quantities affect, respectively, the opacity (and hence depth) of the base of the outer convection zone, the mass of the core, and the thermal properties of the core. The blue loop occurs abruptly and fully developed when the "critical" value of any of these quantities is exceeded, and the effective temperature range and fraction of the lifetime of core helium burning during the slow phase of the blue loop vary surprisingly little. For the recently revised 3a reaction rate, the blue loop always forms. At 30 M, no blue loop occurs for any reasonable set of input parameters — unless the temporary convective intermediate zone (ignored in the present work) extends deeper than does the outer convection zone. For both masses, all passages of the Hertzsprung gap occur on the thermal timescale of the envelope.

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BibTeX Citation

  author={Stothers, R. and Chin, C.-W.},
  title={Stellar evolution at high mass based on the Ledoux criterion for convection},
  journal={Astrophysical Journal},

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RIS Citation

ID  - st07610p
AU  - Stothers, R.
AU  - Chin, C.-W.
PY  - 1973
TI  - Stellar evolution at high mass based on the Ledoux criterion for convection
JA  - Astrophys. J.
JO  - Astrophysical Journal
VL  - 179
SP  - 555
EP  - 568
DO  - 10.1086/151895
ER  -

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