Massive supernovae in binary systems

The presence of a close binary companion can affect the evolution of a massive star through one or more episodes of mass transfer, or by merger in a common-envelope phase. Monte Carlo calculations indicate that similar to 20-35% of all massive supernovae are affected by such processes, and that a substantial fraction of these events will be supernovae of Type II. The properties of the progenitor star, the distribution of circumstellar material, the peak supernova luminosity, the shape of the supernova light curve, and other observable features of the supernova event can be affected by prior binary membership. Binary interactions may be the cause of much of the variability among Type II supernova light curves. In particular, many of the peculiarities of SN 1987A and SN 1993J may well have resulted from the prior duplicity of the progenitors. (C) 1999 Elsevier Science B.V. All rights reserved.