Effects of neutrino degeneracy and of downscatter on neutrino radiation from dense stellar cores

A simplified model is presented for several stages in the development of a neutronization shell in the inner core of a collapsing star. Neutrino degeneracy severely reduces neutrino emission and down scatter in energy, so that for all but the thinnest shell sources, surface emission of an approximately Fermi-Dirac neutrino spectrum obtains. The neutrino spectrum departs from exact Fermi-Dirac form only because of the outstreaming of low-energy neutrinos. A simple equilibrium radiation picture energies in which neutrinos are LTE thermally emitted in the neutronization shell and isotropically coherently scattered by neutrons and by nuclei on the way out of the overlying mantle. The Fermi statistics limit on neutrino flux is probably reached in practice, but is, in most cases, still insufficient for mantle blow-off.