THE GRAIN DYNAMICS IN A REGION OF IONIZED HYDROGEN

Abstract

We consider a grain dynamics in a region of ionized hydrogen around a massive star for estimating a time of setting a grain terminal velocity. We determine the applicability limits for the terminal velocity approx-imation for evolutionary models of ionized hydrogen regions that take into account a relative motion of dust and gas. For that purpose, we solve numerically the equation of motion for dust grains of several kinds typical for massive star forming regions.