THEORETICAL LIGHT-CURVE OF A TYPE IIP SUPERNOVA

The light curve and other observable diagnostics are presented for wha t should be a typical Type II ''plateau'' supernova, the explosion of a 15 M. red supergiant. The calculations are carried out using a multi frequency radiation transport code that includes opacity from all impo rtant mechanisms-bound-bound, bound-free, free-free, and electron scat tering. It is found that the inclusion of opacity sources besides elec tron scattering increases the computed length of the plateau in the 15 M. model by approximately 30 days. Especially important is the ultrav iolet cutoff caused by a thick forest of lines. Deposition and escape of gamma-rays from radioactive decay are also accurately simulated. We find that the presence of 0.06 M. of ejected Ni-56 extends the length of the plateau from approximately 100 days to approximately 140 days. Because of the large hydrogen envelope and radius in this model, mixi ng does not appreciably alter the bolometric light curve, although it does change the gamma-ray light curve significantly. With 0.06 M. of e jected Ni-56, the unmixed (mixed) model peaks in escaping gamma-rays a t 576 (466) days with a gamma-ray luminosity of 3 x 10(38) (7 x 10(38) ) ergs s-1. Except for the local group, the gamma-rays from an extraga lactic 15 M. SNe IIp will be too faint to detect with any existing det ectors. However, a Galactic SNe IIp would be quite bright and easily d etectable.