Supernovae, young remnants, and nucleosynthesis

Supernovae and supernova remnants may be intimately linked to cosmic ray problems as the site of nucleosynthesis, the site of particle acceleration, or both. Although direct evidence for the origin of cosmic rays in supernovae remains elusive, observations of supernovae and their remnants by optical telescopes now provides good evidence that nuclear processing has taken place in these stars. The energetics and spectra of extragalactic supernovae immediately after the explosion indicate that Type I supernovae produce large amounts of iron peak elements. In a complementary way, spectroscopy of the 300 year old galactic remnant Cassiopeia A demonstrates that nuclear processing through oxygen burning took place in that object, which may have been a 15 to 25 solar mass star. The recent discovery of a handful of remnants with abundances like those in Cas A leads to the hope that a detailed correspondence between abundance patterns in these remnants and models for stellar interiors will provide new insight into the last stage of stellar evolution