SN 1987A - The evolution from red to blue

Journal Article · Tue Oct 31 23:00:00 EST 1989 · Astrophysical Journal; (USA)

DOI:https://doi.org/10.1086/168021· OSTI ID:7164002

Tuchman, Y; Wheeler, J C ^[1]

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1. Texas Univ., Austin (USA)

Envelope models in thermal and dynamic equilibrium are used to explore the nature of the transition of SK -69 deg 202, the progenitor of SN 1987A, from the Hayashi track to its final blue position in the H-R diagram. Loci of possible thermal equilibrium solutions are presented as a function of Teff and M(C/O), the mass of the carbon/oxygen core interior to the helium burning shell. It is found that uniform helium enrichment of the envelope results in red-blue evolution but that the resulting blue solution is much hotter than SK -69 deg 202. Solutions in which the only change is to redistribute the portion of the envelope enriched in helium during main-sequence convective core contraction into a step function with Y of about 0.5 at a mass cut of about 10 solar masses give a natural transition from red to blue and a final value of Teff in agreement with observations. It is argued that SK -69 deg 202 probably fell on a post-Hayashi track sequence at moderate Teff. The possible connection of this sequence to the step distribution in the H-R diagram of the LMC. 19 refs.

• OSTI ID: 7164002
• Journal Information: Astrophysical Journal; (USA), Journal Name: Astrophysical Journal; (USA) Vol. 346; ISSN ASJOA; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

640102* -- Astrophysics & Cosmology-- Stars & Quasi-Stellar
Radio & X-Ray Sources
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
DIAGRAMS
ELEMENTS
ERUPTIVE VARIABLE STARS
FLUIDS
GASES
GIANT STARS
HELIUM
HELIUM BURNING
HERTZSPRUNG-RUSSELL DIAGRAM
MASS
MATHEMATICAL MODELS
NONMETALS
RARE GASES
RED GIANT STARS
STAR BURNING
STAR EVOLUTION
STAR MODELS
STARS
SUPERGIANT STARS
SUPERNOVAE
VARIABLE STARS