CHEMICAL HEATING IN STRANGE STARS

As a strange star spins down, its core density increases, changing the chemical equilibrium state of strange matter. The relaxation toward t he new equilibrium state takes a finite time, so the matter is not qui te in chemical equilibrium, and energy is released by reactions at the expense of the stored chemical energy. We study such a chemical heati ng process for a spin-down strange star and find that this effect is s ignificant at later times for weak magnetic fields. We compare the coo ling of a strange star with that of an ordinary neutron star and find that the surface temperature of the strange star is much lower than th at of the neutron star at the age up to 10(8) yr. This favorable to an observational signature for strange stars.