Tsuneo Noda, Masa-aki Hashimoto, Yasuhide Matsuo, Nobutoshi Yasutake, Toshiki Maruyama, Toshitaka Tatsumi, Masayuki Fujimoto
We present a new scenario for the cooling of compact stars considering the central source of Cassiopeia A (Cas A). The Cas A observation shows that the central source is a sort of neutron star which has high effective temperature, and it is consistent with the well known standard cooling model. The observation also gives the mass range of $M \geq 1.5 M_\odot$, which is inconsistent with current plausible cooling scenario of compact stars. There are some cooled compact stars such as Vela or 3C58, which cannot be explained by the standard cooling processes: we invoke some kinds of exotic cooling processes, where a heavier star cools faster than lighter one. However, the scenario seems to be inconsistent with the observation of Cas A. Therefore, we give a new cooling scenario to explain the observation of Cas A by constructing models, which include a quark color superconducting phase with a large energy gap, which appears at ultrahigh density region and reduces neutrino emissivity. In our model, a compact star has color superconducting quark core with low neutrino emissivity surrounded by high emissivity region made by normal quarks. We show cooling curves obtained from the evolutionary calculations of compact stars: while heavier stars cool by the standard scenario, lighter ones indicate opposite tendency.
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http://arxiv.org/abs/1109.1080
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