Without failed supernovae, and accounting for the fact that most massive stars evolve in systems of two or more stars, the rate of Type II and Type Ib/Ic supernovae would be much higher than we observe. read more
Figure 6.8: Artist's illustration of the core of a massive star just prior to a type II supernova explosion. The core is a series of nested spherical shells, with each shell fusing a different element from hydrogen to helium, to carbon, through the periodic table to iron. read more