Radiation hydrodynamical wind revisited: Nonrelativistic regime

Abstract

Abstract We re-examine the radiatively-driven spherical wind under the diffusion and local thermodynamic equilibrium (LTE) approximations, while focusing our attention on the topological nature of critical points. We first consider the nonrelativistic case, where there is no radiation drag and advection luminosity. We find that under the diffusion approximation almost all critical points (loci) are of the nodal type, which is higher order singular points, which makes the solutions stiff. On the other hand, under the LTE approximation, where the diffusive terms do not exist in the source terms, the critical points are of the saddle type, and transonic solutions are not stiff. Although the loci of critical points are quite similar for both approximations in the nonrelativistic regime, the types of critical points are found to be quite different.