Publication Abstracts

Stothers and Chin 1977

Stothers, R., and C.-W. Chin, 1977: Does the upper main sequence extend across the whole H-R diagram. Astrophys. J., 211, 189-197, doi:10.1086/154919.

The effect of using Carson's radiative opacities in evolutionary sequences of stellar models has been studied over the mass range from 7 to 60 M. The opacities are very large in the outer part of the envelope and induce such enormous radii for masses greater than ∼ 30 M (Ze = 0.02) or ∼ 20 M (Ze = 0.04) that the evolutionary tracks during the phase of core hydrogen burning extend across the whole H-R diagram. The choice of the Schwarschild or Ledoux criterion for convection makes very little difference for the behavior of the tracks. Evolution through the effective-temperature range Te = 3.6-4.0 occurs in all cases on a rapid (secular) time scale. Core helium burning takes place exclusively in the red-supergiant configuration for stellar masses > 8 M (Ze = 0.02) or > 6 M (Ze = 0.04). These stellar models seem to be in significantly better agreement with the observed distribution of bright stars on the H-R diagram than are the older models based on the Cox-Stewart opacities. It can be inferred that a large envelope opacity (e.g., Carson's) exists and that substantial mass loss takes place in very massive late-type supergiants.

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BibTeX Citation

@article{st04400m,
  author={Stothers, R. and Chin, C.-W.},
  title={Does the upper main sequence extend across the whole H-R diagram},
  year={1977},
  journal={Astrophys. J.},
  volume={211},
  pages={189--197},
  doi={10.1086/154919},
}

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RIS Citation

TY  - JOUR
ID  - st04400m
AU  - Stothers, R.
AU  - Chin, C.-W.
PY  - 1977
TI  - Does the upper main sequence extend across the whole H-R diagram
JA  - Astrophys. J.
VL  - 211
SP  - 189
EP  - 197
DO  - 10.1086/154919
ER  -

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