The First Order Phase Transition Heating And Thermal Evolution Of Neutron Stars

Compact stars are born in stellar gravitational collapse. The deconfinement phase transition is expected to occur at large densities in the cores of compact stars. The research of the thermal evolution of compact stars is of significant importance for understanding the properties of this mysterious object.The equation of state (EOS) and rotational structure are the base for investigating the thermal evolution of neutron stars. We introduce the EOS and internal structure of rotating neutron stars which include hadron phase, mixed phase and quark phase. The effect of different model bringing to EOS and configuration of star has been investigated. The results show that the soft EOS of hadron phase extends the width of mixed phase and so does the large mass of s quark. The mass of s quark is a prominent factor which influences deformation properties of rotating neutron stars. The large s quark mass can restrain the appearance of a pure quark matter core in neutron stars.Deconfinement phase transition in neutron stars are supposed to be of first order. The release of latent heat in the process of the deconfinement phase transition can affect thermal evolution of stars. Deconfinement phase transition coming from the stellar rotating is an important heating mechanism for compact stars' cooling. By imputing the EOS of mixed phase, and then solving the equation of rotation structure, we self-consistently get the heating rate of deconfinement phase transition.Based on these models of stellar evolution, we get the average energy release of deconfinement phase transition of per nucleon being about 0.1 MeV.The deconfinement heating increase the surface temperature dramatically and influence the thermal evolution of neutron stars. We find the thermal evolution curves are consistent with the observational data (middle age pulsar) despite direct Urca process dominates neutrino emission. In the cases of weak field, stars could maintain high temperatures 10~5K even at older ages 10~9yrs. This feature could be suggested as a preferable explanation for high temperature of low-filed millisecond pulsars at late stage.Comparing the explanation of star models with different constitutions for high temperature mill-second pulsars, we suggest that the high temperature millsecond pulsars expect to be hybrid stars.