A similarity solution for a QSO envelope with radiation driving

For some time now it has been recognized that the wind from a QSO central source is appreciably affected by radiative driving. The present paper outlines an unsteady solution, in terms of a similarity variable, for a model in which the radiative acceleration is either directly proportional to the local fluid density, or is inversely proportional to the square of the radial distance from the (massive) source. The flow is assumed in this model to be spherically symmetric and externally bounded by a shock wave, expanding into a medium at rest. (author)