A new study of an old sink of sulfur in hot molecular cores: the sulfur residue

Abstract

Sulfur appears to be depleted by an order of magnitude or more from its elemental abundance in star-forming regions. In the last few years, numerous observations and experiments have been performed in order to to understand the reasons behind this depletion without providing a satisfactory explanation of the sulfur chemistry towards high-mass star-forming cores. Several sulfur-bearing molecules have been observed in these regions, and yet none are abundant enough to make up the gas-phase deficit. Where, then, does this hidden sulfur reside? This paper represents a step forward in our understanding of the interactions among the various S-bearing species. We have incorporated recent experimental and theoretical data into a chemical model of a hot molecular core in order to see whether they give any indication of the identity of the sulfur sink in these dense regions. Despite our model producing reasonable agreement with both solid-phase and gas-phase abundances of many sulfur-bearing species, we find that the sulfur residue detected in recent experiments takes up only ~6 per cent of the available sulfur in our simulations, rather than dominating the sulfur budget.

13 pages, 6 colourful figures, accepted by MNRAS

References in corpus (5)

• A Unified Representation of Gas-Phase Element Depletions in the Interstellar Medium
• Desorption From Interstellar Ices
• Faint emission lines in the Galactic H II regions M16, M20 and NGC 3603
• S-bearing molecules in Massive Dense Cores
• First evidence for molecular interfaces between outflows and ambient cloud in high-mass star forming regions?

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