The rp-process in neutrino-driven winds

Recent hydrodynamic simulations of core-collapse supernovae with accurate neutrino transport suggest that the bulk of the early neutrino-heated ejecta is proton rich, in which the production of some interesting proton-rich nuclei is expected. As suggested in recent nucleosynthesis studies, the rapid proton-capture (rp) process takes place in such proton-rich environments by bypassing the waiting point nuclei with beta(+)-lives of a few minutes via the faster capture of neutrons continuously supplied from the neutrino absorption by protons. In this study, the nucleosynthesis calculations are performed with a wide range of neutrino luminosities and electron fractions (Ye), using semianalytic models of proto-neutron-star winds. The masses of proto-neutron stars are taken to be 1.4 and 2.0 M-circle dot, where the latter is regarded as the test for somewhat high-entropy winds (about a factor of 2). For Ye > 0: 52, the neutrino- induced rp-process takes place in many wind trajectories, and p-nuclei up to A similar to 130 are synthesized in interesting amounts. However, Mo-92 is somewhat underproduced compared to other p-nuclei with similar mass numbers. For 0: 46 < Ye < 0: 49, on the other hand, 92Mo is significantly enhanced by the nuclear flows in the vicinity of the abundant Zr-90 that originates from the alpha-process at higher temperature. The nucleosynthetic yields are averaged over the ejected masses of winds, and further, over the Ye distribution predicted by a recent hydrodynamic simulation of a core-collapse supernova. Comparison of the Ye-and mass-averaged yields to the solar compositions implies that the neutrino- driven winds can potentially be the origin of light p-nuclei up to A similar to 110, including Mo-92,Mo-94 and Ru-96,Ru-98, that cannot be explained by other astrophysical sites.