Signal of quark deconfinement and thermal evolution of hybrid stars

It is well known that neutron stars spin down due to magnetic dipole radiation. The deconfinement phase transition of hadron matter to quark matter is expected to occur in the dense cores of the stars during spin-down. The phase transition continuously takes place inducing not only structural changes but also energy release in case of a first-order phase transition. The generation of energy increases the internal energy of the stars which is called deconfinement heating. The temperature of the stars arise when the deconfinement heating appears in the cores. We explore the deconfinement signature by studying the changes of surface temperature in the thermal evolution process of neutron stars.