ABSTRACT
The predominant cooling mechanism of hot newly formed neutron stars immediately after formation is neutrino emission, with an initial cooling time scale of seconds. Being sensitive to the adopted nuclear equation of state, the neutron star mass, the assumed magnetic field strength, the possible existence of superfluidity, meson condensates, and quark matter, theoretical cooling calculations provide most valuable information about the interior hadronic matter and neutron star structure. The energy radiated away by a star is supported from its rest mass by nuclear burning, from its gravitational and internal energy by quasi-static contraction, or from both sources by both processes. Energy is transported from the hot interior of a star toward its cool surface by a combination of diffusing photons, escaping neutrinos, heat conduction in the stellar material, and convective motions of the stellar material. The chapter considers a stellar environment where photon transport is diffusive.
