Shock propagation in supernovae

In this paper we discuss circumstances under which whock waves, formed in the collapse of large stars, will propagate outwards, blowing off the mantle and envelope of these stars. This is a mechanism for the formation of neutron stars. We introduce the concept of 'net ram pressure'; in terms of this quantity our book-keeping is conveniently carried out. The formation of a 'dense pack', a region at the center of the collapsed stellar core at densities above nuclear matter density, is essential for successful shock formation and propagation. Effects of nuclear excited states and nuclear dissociation are conveniently expressed in terms of the net ram pressure. We construct pre-supernova cores of 1.25 Msub(sun) and 1.35 Msub(sun), and perform hydrodynamical calculations using them as input, which give marginally successful and unsuccessful results, respectively. Low entropy for the initial core and the thinning out of matter falling through the shock wave turn out to be essential for success. (orig.)