Cooling of neutron stars (NSs) with the cores composed of neutrons, protons and electrons is simulated assuming ¹S₀ superfluididy of neutrons in the NS crust and outermost core, as well as ¹S₀ superfluidity of protons and ³P₂ superfluidity of neutrons in the NS core. We consider different equations of state (EOSs) in the NS cores and different density profiles of superfluid critical temperatures of nucleons, T_c(\rho), and we confront the cooling models with observations of thermal emission from eight isolated middle-aged NSs. All observational data can be explained by cooling of NSs of different masses M with given EOS and critical temperatures T_c(\rho). In all cases, ³P₂ neutron pairing should be weak, T_c < 10⁸ K. We treat five objects (1E 1207--52, RX J0002+62, Vela, PSR 0656+14, and Geminga) as NSs where direct Urca process is allowed but greatly reduced by a strong proton superfluidity. In this way we can determine NS masses for a given proton superfluidity, T_cp(\rho). We treat RX J0822-43, PSR 1055-52 and RX J1856-3754 as low-massive NSs where direct Urca process is forbidden. To explain relatively high surface temperatures of these three objects one needs a density profile of the neutron superfluidity in the crust with rather high and flat maximum. Their interpretation is affected also by the presence of NS surface magnetic fields and heat-blanketing surface laeyrs composed of light elements.

Page created by Alexander Potekhin (palex.astro@mail.ioffe.ru) on September 24, 2001.