Neutrino energy loss rates due to 66-71Ni in stellar matter

Abstract

Abstract Rates for (anti-)neutrino energy loss on nickel isotopes, due to interactions involving weak decays (β±-decay and lepton captures) are regarded as having fundamental importance during late evolutionary stages of massive stars. These rates substantially affect the leptonic ratio (Ye) of stellar interior. For the densities less than 1011 g/cm3, weak processes produce (anti-)neutrinos which cause reduction in the stellar core’s entropy. In this paper, rates for neutrino and anti-neutrino energy loss on nickel neutron-rich isotopes (66-71Ni) have been presented. Rates for energy loss have been determined by applying the deformed pn-QRPA model. The ranges for temperature and density, have been used to determine the rates, are from 0.01 to 30 (109 K) and 101 to 1011 (g/cm3), respectively. Our computed rates for energy loss, at higher temperature regions, are enhanced in comparison with previously reported rates of Pruet and Fuller (PF).