The Equation of State and General Relativity in Supernovae.

The results of an extensive numerical study of the outcome of massive star collapse and subsequent shock formation and propa- gation are presented. The stiffness of the equation of state at high density is shown to play a crucial role, a softer equation of state being helpful to shock production and propagation. The effect of neutrinos is investigated in a simple manner by varying the neutrino transport from a simple trapping density to a simple leakage scheme. With a softer equation of state the maximum central densities reached are high enough that general relativity may become impor- tant. The effects of general relativity are investigated in detail. It is shown that while general relativity is generally harmful to the shock, once the equation of state becomes soft enough, general relativistic effects may conspire to transfer large amounts of energy from the gravitational field to the shock, resulting in powerful explosions. This is first investigated using simplified initial conditions, the initial models being constructed in an ad hoc fashion to facilitate numerical investigation. Finally, results are presented for detailed pre-supernova initial models of 12 and 15 M(,o). These models do explode, with explosion energies varying from (TURN)1 - 3 x 10('51) ergs depending on the degree of softness of the high density equation of state.