Neutrino emissivity of nonequilibrium processes with nucleon superfluidity

We investigate the influence of nucleon superfluidity on the neutrino emissivity of nonequilibrium β processes. Calculations of the reduction factors for direct and modified Urca processes with three types of nucleon superfluidity in npe matter are performed. The numerical results are given because the analytical solution is impossible. We find that the superfluid influence is closely related to the chemical departure from β equilibrium. For a small chemical departure, the superfluid reduction factor depends almost only on the gap and is hardly affected by the departure, while for a large enough departure, it rapidly enhances neutrino emissivity. The onset of ”enchanced” emission has some corresponding thresholds that seem to be linked to the ratio of the energy gap to the chemical departure.