The energetics of adiabatic shocks in stellar collapse

The energetics of shocks from stellar collapse are examined analytically. A general minimal condition is derived for outward shock propagation. Current hydrodynamic studies which indicate that the shock stalls are shown to be consistent with the analytic criteria. The dominant factor behind the failure of the shock is nuclear dissociation. It is shown that dissociation must occur over essentially the whole outer mantle if a respectable shock propagates. This and the results of current hydrodynamic studies then indicate that collapsing iron cores more massive than about 1.3 solar masses do not explode.