Strangeness, condensation, nucleon superfluidity, and cooling of neutron stars

We present results from a study of the cooling of neutron stars. We use a variety of equations of state and particularly examine the effects of "exotic" matter (e.g., pion or kaon condensates, quark matter) at the center of the star. We also study the effect of superfluidity in the core and crust. We find that in order to fit the observed young neutron stars, the Crab, 3C 58, and RCW 103 (with ages similar to 10(3) yr) that superfluidity is required, but no exotic matter is needed. In order to fit the observed temperature of the Vela pulsar (whose age is similar to 10(4) yr), we need both superfluidity and some "exotic" matter at the center. We conclude that Vela is a star with larger mass than the other three and hence has a higher density in the center, at which the exotica are produced. By altering the critical temperature for superfluidity, T-crit, we can accommodate a variety of exotica.