Neutrino emissivities of neutron stars.

TLDR: In this article, the neutrino mean free path arising from a reaction related to the Urca process is calculated, and the influence of finite neutrinos mean free paths and nucleon superfluidity on neutrini emissivities is briefly discussed.

Abstract: Neutrino emissivities from the modified Urca process, considered previously by Bahcall and Wolf, and neutrino pair bremsstrahlung from nucleon-nucleon scattering, considered previously by Flowers et al., are recalculated using a nucleon-nucleon interaction that consists of a long-range, one-pion-exchange tensor part and a short-range part parametrized with nuclear Fermi liquid (Landau) parameters. Effects of short-range correlations on the tensor part are approximated through insertion of a cutoff in the one-pion exchange potential. The resulting emissivities differ dramatically from previous calculations: the emissivities from the Urca process and the neutron-neutron neutrino pair bremsstrahlung exceed the results of Bahcall and Wolf and Flowers et al., respectively, by an order of magnitude. It is argued that these results are due to the one-pion-exchange tensor force in the nucleon-nucleon interaction used here. The neutrino mean free path arising from a reaction related to the Urca process is also calculated, and the influence of finite neutrino mean free path and nucleon superfluidity on neutrino emissivities is briefly discussed.