On the cooling of neutron stars

Abstract

It has recently been pointed out that many models of dense nuclear matter allow the direct URCA process in highly dense systems like neutron stars. In view of this, we have calculated the energy loss in dense nuclear matter as a result of such processes at finite temperatures. For the description of nuclear matter we have used Walecka's mean-field theory. For the neutrino emissivity rates we have employed the Iwamoto model and evaluated the angular integrals involved exactly. We find that the emissivity rate is density dependent, being almost a constant at high densities, while at low densities it shows an exponential behaviour with temperature rather than the usual power law.