2 EFFECTS IN SLOWLY EVOLVING DISSIPATIVE SELF-GRAVITATING SPHERES

We study the slow evolution of spherically symmetric fluid distributio ns undergoing dissipation in the form of a radial heat flow. We analyz e three examples and show that, depending on the heat flow distributio n, different signs in the velocity of fluid elements may appear, givin g rise to the splitting of the configuration. It is also shown that wh enever the slowly evolving regime is compatible with very strong gravi tational fields, the heat flux becomes negative (directed inward), and the fluid will eventually expand.