Two effects in slowly evolving dissipative self-gravitating spheres

We study the slow evolution of spherically symmetric fluid distributions undergoing dissipation in the form of a radial heat flow. We analyze three examples and show that, depending on the heat flow distribution, different signs in the velocity of fluid elements may appear, giving rise to the splitting of the configuration. It is also shown that whenever the slowly evolving regime is compatible with very strong gravitational fields, the heat flux becomes negative (directed inward), and the fluid will eventually expand.