Binary Models for the Progenitor of SN 1987A

Abstract

A significant fraction of all stars are in binaries. It is thus reasonable to examine the possibility that the progenitor of SN 1987A was a component of a binary system. We here consider some of the ranges of parameter space in which binary evolution produces progenitors that are applicable to models of SN 1987A [1, 2, 3]. Other binary models have been proposed by FABIAN et al. [4] and CHEVALIER and SOKER [5]. Such models may help to explain several of the anomalies of this supernova, including the blue color of the progenitor, the asymmetries in the ejecta, the barium anomaly, and the mystery spot (see [1, 2, 3] for further discussion and references). Unlike many single-star models (see [1, 2, 3] for references), the fits of these models to the observations do not rely on the assumption of low metallicity, a non-standard treatment of convection, and/or the ad hoc stipulation of severe mass loss from the presupernova star. The binary models presented here make definite predictions that can be checked against observations; moreover, the models are sufficiently general that the results may be relevant to other supernovae as well.