Structure of Hot Strange Quark Stars: an NJL Model Approach at Finite Temperature

In this paper, we investigated the thermodynamic properties of strange quark matter using the Nambu-Jona-Lasinio (NJL) model at finite temperatures where we considered the dynamical mass as the effective interaction between quarks. By considering the pressure of strange quark matter (SQM) at finite temperatures, we showed that the equation of state of this system gets stiffer with increasing temperature. In addition, we investigated the energy conditions and stability of the equation of state and showed that the equation of state of SQM satisfies the conditions of stability. Finally, we computed the structure properties of hot strange quark stars (SQS) including the gravitational mass, radius, Schwarzschild radius, average density, compactness, and gravitational redshift. Our calculations showed that in this model, the maximum mass and radius of SQS increase with increasing temperature. Furthermore it was shown that the average density of SQS is greater than the normal nuclear density, and it is an increasing function of temperature. We also discussed the temperature dependence of the maximum gravitational mass calculated by different methods.