Electron capture supernovae - One-zone collapse calculation for stars with masses 10 solar masses and 15 solar masses

Abstract

The equilibrium values of the lepton fraction, the entropy, and other thermodynamic variables are evaluated in a one-zone collapse calculation based on an analytic equation of state for hot, dense matter. The electron capture rates that take account of the forbidden capture and thermal excitation modes in the neutron-shell blocked region are used, and a diffusion scheme for neutrino transport is adopted. It is found that the results are sensitive to a variation in the input physics such as the efficiency of the neutrino trapping and also to the presupernova configurations for 10 and 15 solar mass stars. The possibility that the neutron-rich nuclei may have nonspherical shapes and the effect on the onset of neutron shell blocking are examined.