Effect of radioactivity on type 2 supernova outburst

The effect of a slow release of energy due to Ni-56 yields Co-56 yields Fe-56 decay on the course of type 2 supernovae (SN 2) in the plateau-like phase of their light curves is investigated. The admixture of radioactive Ni-56 to matter of the SN 2 envelopes is shown to make the plateau longer with simultaneous increase in luminosity. The radioactive heating also slows the cooling of the SN 2 envelopes which may be of importance for interpretation of the supernova spectra. The abundance of Ni-56 in the SN 2 envelopes seems, however, difficult to estimate from observations of the light curves since only radioactive decay has such influence on the light curve morphology which is in the first approximation indistinguishable from that produced by a certain increase in the presupernova radius. It is emphasized that not only radioactivity but a slow transport of energy from collapsed stellar remnant (neutron star) to expanding envelope may be of specific value for detailed theory of SN 2 outburts as well.