Spherical configuration of a super-dense hot compact object with particular EoS

Abstract

The equation of state (EoS) $P=P(\rho ,...)$ -- pressure as a function of density and other thermodynamical quantities -- is what generates particularities of mass--radius distribution $M(R)$ for super--dense compact stellar bodies, the remnants of cosmic cataclysms. In view of recent nuclear experiments, we propose one particular EoS, which admits the critical state characterized by density ${\rho }_c$ and temperature $T_c$, and which under certain conditions permits a radial distribution of the super--dense matter in "liquid" phase. We establish such conditions and demonstrate that a stable configuration is indeed possible (only) for temperatures smaller than the critical one. Using Tolman--Oppenheimer--Volkoff equations for hydrostatic equilibrium, we derive the mass--radius relation for the super--dense compact objects with masses smaller than the Sun, $M\ll M_{\odot }$. The obtained results are within the constraints established by both heavy--ion collision experiments and theoretical studies of neutron--rich matter.

Comments: 11 pages, 21 figures