Recently, Elshamounty et al. performed a reanalysis of the surface temperature of the neutron star in the supernova remnant Cassiopeia A on the basis of Chandra data measured during the last decade and added a new data point. We show that all reliably known temperature data of neutron stars including those belonging to Cassiopeia A can be comfortably explained in our “nuclear medium cooling” scenario of neutron stars. The cooling rates account for medium-modified one-pion exchange in dense matter, polarization effects in the pair-breaking-formation processes operating on superfluid neutrons and protons paired in the $1S_0$ state, and other relevant processes. The emissivity of the pair-breaking-formation process in the $3P_2$ state is a tiny quantity within our scenario. Crucial for a successful description of the Cassiopeia A cooling proves to be the thermal conductivity from both the electrons and nucleons being reduced by medium effects. Moreover, we exploit an equation of state which stiffens at high densities due to an excluded volume effect and is capable of describing a maximum mass of $2.1M_{\odot }$, thus including the recent measurements of PSR J1614-2230 and PSR J0348+0432.

• Received 27 August 2013

DOI:https://doi.org/10.1103/PhysRevC.88.065805