RELATIVISTIC GRAVITATIONAL COLLAPSE IN COMOVING COORDINATES: THE POST-QUASISTATIC APPROXIMATION

A general iterative method proposed some years ago for the description of relativistic collapse is presented here in comoving coordinates. For doing that we redefine the basic concepts required for the implementation of the method for comoving coordinates. In particular, the definition of the post-quasistatic approximation in comoving coordinates is given. We write the field equations, the boundary conditions and a set of ordinary differential equations (the surface equations) which play a fundamental role in the algorithm. As an illustration of the method, we show how to build up a model inspired by the well-known Schwarzschild interior solution. Both the adiabatic and the nonadiabatic case are considered.