THE EVOLUTION OF PROTOSTARS .3. THE ACCRETION ENVELOPE

[[abstract]]The radiation gas dynamics of the rapidly inflowing material during the main accretion phase of protostellar evolution is considered. The momentum and energy transfer by radiation and matter, the dissociation of the molecular gas, and the thermochemical destruction of graphite grains are followed in detail. Considerable physical insight is gained by taking advantage of the vastly disparate time and length scales associated with the various processes. Different computational techniques are used in different portions of the accretion flow: the optically thick dust envelope, the thermalization layer of stellar photons, the opacity gap, and the radiative precursor (if one exists). The evolution of the envelope of a protostellar model whose hydrostatic core was described in an earlier communication is summarized. --------------------------------------------------------------------------------[[fileno]]2010118010106[[department]]物理