Abstract
We use observable properties of Type IIP (core-collapse) supernovae to obtain improved insight into the type of star which explodes, the range of masses of radioactive material produced and its effect on other observable properties. Because, we now have a small sample of reasonably frequently observed Type IIP SNe, we have used the light curves to obtain the mass of
56Co produced, a method exploited for the well observed SN 1987A. With these determinatiots, we can demonstrate a correlation between the mass of
56Co and the rate of decline of the visible light curve (V) from plateau to exponential decay. This provides a distance-independent method for determining the mass of
56Co. The availability of spectra in the phase interval 200–400 days allows us to demonstrate a good correlation between the luminosity of H
α and the
56Co mass. More observed SNe with improved sampling would strengthen these conclusions.