Sulfuretted Molecules in Hot Cores

摘要

The chemistry of sulfur-bearing molecules that result from grain-mantle evaporation into warm gas is described. Evaporation of ices, in which all the available sulfur is contained in H_2S, drives a hot- phase chemistry that produces SO, SO_, CS, OCS, and H2CS. It is predicted that S_2 can attain significant abundances in hot cores. Large variations in abundances occur as a core evolves, and eventually almost all the original H2S is converted to SO and SO_2. The SO/H_2S and SO/SO_2 abundance ratios could be useful as a crude molecular clock to measure the time since mantles were disrupted.