Progenitor structure of SN 1987A

Abstract

view Abstract Citations (26) References (22) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Progenitor Structure of SN 1987A Barkat, Zalman ; Wheeler, J. Craig Abstract A careful examination is made of the structure of the progenitor of SN 1987A, presumed to be SK -69^deg^202. Adopting values for the luminosity and effective temperature in the observed range, the equations of stellar structure are integrated inward assuming dynamic and thermal equilibrium. For fixed luminosity, helium core mass, and envelope composition, self-consistent solutions for the envelope mass fall into two families. For solar hydrogen abundance, X ~ 0.70-0.75, one set of solutions has large envelope mass corresponding to the main-sequence mass being virtually intact, and the other set of allowed solutions has very small envelope mass, ~0.1 M_sun_. This accounts for the dichotomy of some models in the literature. The solutions with large envelope mass are difficult to reconcile with indications of composition anomalies, e.g., enhanced helium, nitrogen, and barium in the envelope. The models with small envelope mass can be ruled out because they would eject the hydrogen with excessive speed in the explosion, and give a light curve that rises too rapidly to an excessively bright peak. The range of excluded envelope mass decreases as the helium content of the envelope is increased. For Y >~ 0.5, no envelope solutions can be excluded on purely structural grounds. Current evidence suggests that the envelope of SK -69^deg^202 consisted of least several solar masses of helium-enriched matter. For fixed luminosity, total mass, core mass, and core radius, a triple-valued set of solutions can be found for the structure as a function of effective temperature. One of the solutions corresponds to the Hyashi track, but the other two can represent blue supergiants with different core and envelope structure. In constructing models for the progenitor of SN 1987A, care must be taken that envelopes of arbitrary mass and luminosity are not appended inconsistently onto cores of specified properties. Publication: The Astrophysical Journal Pub Date: September 1988 DOI: 10.1086/166649 Bibcode: 1988ApJ...332..247B Keywords: Stellar Cores; Stellar Envelopes; Stellar Evolution; Stellar Mass; Stellar Structure; Supernova 1987a; Blue Stars; Helium; Hydrogen; Light Curve; Stellar Luminosity; Supergiant Stars; Temperature Gradients; Astrophysics; STARS: INDIVIDUAL ALPHANUMERIC: SN 1987A; STARS: INTERIORS; STARS: SUPERNOVAE full text sources ADS | data products NED (2) SIMBAD (1)