Narrow Results

In this paper, we employ the Karmarkar condition to model a spherically symmetric radiating star undergoing dissipative gravitational collapse within the framework of classical general relativity. The collapse ensues from an initial static core satisfying the Karmarkar condition in isotropic coordinates and proceeds nonadiabatically by emitting energy in the form of a radial heat flux to the exterior Vaidya spacetime. We show that the dynamical nature of the collapse is sensitive to the initial static configuration that inherently links the embedding to the final remnant. Our model considered several physical tests on how an initially static stellar structure onset to a radiative collapse.

The decreasing of the inertial mass density, established in the past for dissipative fluids, is found to be produced by the "inertial" term of the transport equation. Once the transport equation is coupled to the dynamical equation, one finds that the contribution of the inertial term diminishes the effective inertial mass and the "gravitational" force term, by the same factor. An intuitive picture and prospective applications of this result to astrophysical scenarios are discussed.

A recent study of dissipative collapse considered a contracting sphere in which the areal and proper radii are equal throughout its evolution. The interior space–time was matched to the exterior Vaidya space–time which generated a temporal evolution equation at the boundary of the collapsing sphere. We present a solution of the boundary condition which allows the study of the gravitational and thermodynamical behavior of this particular radiating model.

In this paper, we investigate the effect of charge on the collapse of a radiating, shearing sphere. The junction conditions required for the smooth matching of a general spherically symmetric spacetime (in the absence of rotation) to the exterior Vaidya–Reissner–Nordström leads to a temporal evolution equation at the boundary of the collapsing star. We are in a position to integrate these equations in the presence of charge and shear. The solutions obtained here are new and generalize recent treatments of dissipative, shearing collapse to the charged case.