Quasi-static thermal evolution of compact objects

We study under what conditions the thermal peeling is present for dissipative local and quasi-local anisotropic spherical matter configurations. Thermal peeling occurs when different signs in the velocity of fluid elements appear, giving rise to the splitting of the matter configuration. The evolution is considered in the quasi-static approximation and the matter contents are radiant, anisotropic (unequal stresses) spherical local, and quasi-local fluids. The heat flux and the associated temperature profiles are described by causal thermodynamics consistent with this approximation. It is found that both types of configurations can exhibit thermal peeling when most of the radiated energy emerges from the first half of the distribution, and thermal peeling appears to be associated with extreme astrophysical scenarios (highly relativistic and very energetic gravitational system).

A CAUSAL MODEL FOR A CLOSED UNIVERSE

We study a closed model of a universe filled with viscous fluid and quintessence matter components. The dynamical equations imply that the universe might look like an accelerated flat Friedmann–Robertson–Walker (FRW) universe at low redshift. We consider here dissipative processes which obey a causal thermodynamics. Here, we account for the entropy production via causal dissipative inflation.

COSMOLOGICAL MODELS IN GENERALIZED SCALAR–TENSOR THEORY WITH CAUSAL VISCOUS FLUID

We consider generalized Brans–Dicke theory in which the coupling parameter is not constant but a function of the scalar field. Friedmann–Robertson–Walker models with bulk viscous fluid source described by full (i.e., nontruncated) causal nonequilibrium thermodynamics are analyzed. Exact solutions for the flat case have been obtained. Our results are compared with those in the usual Brans–Dicke theory with causal thermodynamics.