  An evolution of radiant shock wave front is considered in the framework of a
recently presented method to study self-gravitating relativistic spheres, whose
rationale becomes intelligible and finds full justification within the context
of a suitable definition of the post-quasistatic approximation. The spherical
matter configuration is divided into two regions by the shock and each side of
the interface having a different equation of state and anisotropic phase. In
order to simulate dissipation effects due to the transfer of photons and/or
neutrinos within the matter configuration, we introduce the flux factor, the
variable Eddington factor and a closure relation between them. As we expected
the strength of the shock increases the speed of the fluid to relativistic
values and for some critical ones is larger than light speed. In addition, we
find that energy conditions are very sensible to the anisotropy, specially the
strong one. As a special feature of the model, we find that the contribution of
the matter and radiation to the radial pressure are the same order of magnitude
as in the mant as in the core, moreover, in the core radiation pressure is
larger than matter pressure.
