Author(s): , ,
Institution(s): 1. Denison University, 2. Ohio University Lancaster
The evolution of gas and dust during protostellar infall and collapse has been significantly discussed for low mass stars, but in much less detail for high-mass stars. In particular, while gas-phase chemistry has been considered previously, the inclusion of grain-surface chemistry - and its subsequent impact on gas-phase species - has not. In this work, we model the evolution of the dust and gas chemistry for gas infalling toward a high-mass protostar. We include the time-dependent temperature and luminosity evolution of the protostar itself, and the ensuing impacts on the temperature structure within the envelope as the gas infalls. Multiple infall scenarios are considered, including both a Shu-type inside-out collapse and logotropic and polytropic collapse. The canonical "step-function" abundance profile is naturally reproduced. The results are compared with existing observations of water, as well as other species. Implications for other future observations are discussed.