Gravitational-collapse supernovae

The gravitational collapse of the core of a massive star releases ample energy for a supernova explosion. The mechanisms by which this energy can be imparted to the outer parts of the stars to actually yield an explosion is outlined, and some of the related physical processes are examined. In particular the generation of entropy and the loss of neutrinos during the collapse of the core and the generation of lepton-driven buoyancy instabilities are discussed in some detail.