A binary evolutionary model for the progenitor of SN 1987A.

In this paper we explore the hypothesis that the blue progenitor of SN 1987A was a component of a close binary. It is shown that a blue spectral appearance at the end of core helium burning (and possibly also during the following evolutionary phases) is a natural phenomenon for a star with initial mass between 9M_sun_ and 15M_sun_ which was originally in a close binary with mass ratio q~1 and who accreted at least 8-10M_sun_ while already being a hydrogen shell burning star. This phenomenon does not depend on the exact treatment of the convective core overshooting, the stellar wind mass loss rate, the metallicity. A blue SN progenitor in the Galaxy would therefore not be a surprise.