EMISSIVITIES OF NEUTRINOS IN NEUTRON-STAR CORES

In this work we consider various URCA processes relevant for neutrino emissions in the core region of neutron stars. The parameters which en ter these processes, such as effective masses, proton pairing gaps, pr oton fractions, and electron and muon chemical potentials, are calcula ted in a self-consistent Brueckner-Hartree-Fock approach for beta-stab le nuclear matter. Modern meson-exchange potential models are employed . We find that the emissivities from modified URCA processes are reduc ed due to the presence of superconducting protons at densities below 0 .4 fm(-3).