The Structure And Cooling Of Neutron Stars

Because of the uncertainty of the nuclear physics theory, if possible, there are all sorts of freedom under the energy scale of neutron stars. For the different equations of state, after solving the relativistic stellar structure equations, we will obtain the different mass-radius trajectories, which should be examined from observations. On the other hand, The dynamic processes among different microcosmic compositions within stars are not completely the same, which may lead to different thermal cooling phenomena. Therefore, when we compare the cooling curve with the data of thermal radiation, we can also get the informations of the dense matter inside the star.In order to explain the old stars with high temperature we found, when we study the late cooling of neutron stars, we have to take the heating mechanisms into account. The rotochemical heating is an important mechanism for the thermal evolution of old neutron stars, which originates in deviations from beta equilibrium due to spin-down compression. Because the time scale of relaxation is longer than the spin-down compression’s, the system is permanently out of chemical equilibrium. This implies an storage of chemical energy, which is dissipated by heat generation, making the temperature of the neutron stars go up to a quasi-equilibrium state.When the neutron stars with mixed phase spin down and compress, the decon-finement phase transition may occur. Hadron matter are converted into quark matter in the interior, and result in the displacement of equilibrium state and the dissipation as well. Taking the material distribution and rotation structure into account, we can find that the deconfinement phase transition is able to raise the chemical heating efficiency, and the heating effect can be reflected in high magnetic field neutron stars.In consideration of that the neutrino radiation from unbalanced Urca reactions can also dissipative the stored chemical energy, this new dissipation mechanism has been discussed in this paper. According to the calculation, we find that this mecha-nism has only a little influence on the cooling curve.