Large magellanic cloud helium-rich peculiar blue supergiants and SN 1987A

Y. Tuchman*, J. Craig Wheeler

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

17 Scopus citations


The theoretical distribution of massive stars in the H-R diagram is compared to the revised data of Fitzpatrick and Garmany for the LMC. Preferred models of ∼20 M undergo a thermal contraction at Teff∼ 35,000 K at the end of core hydrogen burning but reestablish thermal equilibrium to the red of the main sequence at Teff ∼20,000 K after ignition of a hydrogen-burning shell. They then evolve on a nuclear time scale to Teff ∼6000 K where they lose thermal equilibrium and jump to the Hayashi track. The theoretical and observed distributions agree with two significant exceptions: the blue thermal contraction "gap" is overpopulated compared to the theory, and there is a "ledge" crossing the center of the H-R diagram. We explore the hypothesis that some of the observed stars in the blue "gap" are secondaries that have accreted heliumrich matter from deep within the hydrogen envelope of a red supergiant primary. Some preliminary observational justification is given. Other features of the observed H-R diagram and alternative modes of evolution are also discussed along with implications for Type Ib supernovae and SN 1987A.

Original languageAmerican English
Pages (from-to)255-264
Number of pages10
JournalAstrophysical Journal
Issue number1
StatePublished - 1 Nov 1990


  • Stars: evolution
  • Stars: individual (SN 1987A)
  • Stars: interiors
  • Stars: late-type
  • Stars: supernovae


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