RADIATING COLLAPSE OF A HEAT-CONDUCTING-FLUID SPHERE WITH CONFORMALLYFLAT INTERIOR

The relativistic gravitational collapse of a sphere filled with a heat -conducting fluid in shear-free and radial motion is considered. The s phere's exterior is described by Vaidya's outgoing metric, while we ha ve a conformally flat interior. We present a particular solution for t he interior's metric coefficients and then we study the dynamics of th e collapse. Finally, we give some thermodynamic considerations in the frame of Eckart's theory of dissipative relativistic fluids accompanie d by the diffusion approximation for the radiation transport.