NEUTRON-RICH ALPHA-RICH FREEZE-OUT AND THE R-PROCESS IN THE HIGH-ENTROPY NEUTRINO-ENERGIZED SUPERNOVA BUBBLE

The high-entropy alpha-rich freeze-out of neutron-rich nuclei suggeste d by Woosley and Hoffman and the subsequent formation of r-nuclides ar e studied in the framework of a recent supernova model. The calculatio ns are performed with the help of a single reaction network that is ab le to describe the establishment of the nuclear statistical equilibriu m, the charged-particle reaction freeze-out, and the subsequent neutro n captures and beta-decays that produce the r-nuclides. We analyze the effect of using various models for the nuclear binding energies, and in particular the new Extended Thomas-Fermi plus Strutinsky Integral m ethod and the finite-range droplet model. These nuclear mass models ar e also used to calculate the beta-decay rates with the gross theory. W e delineate the range of entropies necessary to produce a solar-system -like distribution of the r-nuclides. We also discuss in detail how th e freeze-out affects the final r-process abundance distribution.