The Chemistry of Phosphorus in Hot Molecular Cores

Hot molecular cores in star-forming regions are known to have gas-phase chemical compositions determined by the material evaporated from the icy mantles of interstellar grains, followed by subsequent reactions in the gas phase. Current models suggest that the evaporated material is rich in hydrogenated species. In this paper we consider the chemistry induced in a hot core by the release of phosphine, PH 3 , from interstellar grains. We nd that PH 3 is rapidly destroyed by a series of reactions with atomic hydrogen and is converted, within 10 4 yrs, into atomic P, and PO and PN, with P atoms being the most abundant species. Other phosphorus-bearing molecules can be formed in the hot gas but on timescales long compared to those of the hot cores.