Estimate of the ionization and mass of the envelopes of type I supernovae on the basis of the radioactive-decay hypothesis

An analysis of spectra of supernovae obtained in 1972 confirms the hypothesis that the radioactive decay of Ni-56 is responsible for the exponential portion of the light curves of type I supernovae. The interaction of positrons formed in the beta decay of Co-56 with matter ejected during the explosion of the envelope is studied, which makes is possible to determine the ionization of the envelope. It appears that the main source of free electrons in the envelope is helium, the most abundant of the elements there; iron tends to dominate the second stage of ionization. In this case, the mass of the envelope of 0.6 solar mass, and its kinetic energy is about 5 x 10 to the 50th erg. It is concluded that neutron stars are formed in the explosions of type I supernovae as well as in explosions of type II supernovae.