Deuterium chemistry of dense gas in the vicinity of low-mass and massive star forming regions

Abstract

The standard interstellar ratio of deuterium to hydrogen (D/H) atoms is $\sim 1.5\times 10^{-5}$. However, the deuterium fractionation is in fact found to be enhanced, to different degrees, in cold, dark cores, hot cores around massive star forming regions, lukewarm cores, and warm cores ({\it hereafter}, hot corinos) around low-mass star forming regions. In this paper, we investigate the overall differences in the deuterium chemistry between hot cores and hot corinos. We have modelled the chemistry of dense gas around low-mass and massive star forming regions using a gas-grain chemical model. We investigate the influence of varying the core density, the depletion efficiency of gaseous species on to dust grains, the collapse mode and the final mass of the protostar on the chemical evolution of star forming regions. We find that the deuterium chemistry is, in general, most sensitive to variations of the depletion efficiency on to grain surfaces, in agreement with observations. In addition, the results showed that the chemistry is more sensitive to changes in the final density of the collapsing core in hot cores than in hot corinos. Finally, we find that ratios of deuterated sulphur bearing species in dense gas around hot cores and corinos may be good evolutionary indicators in a similar way as their non deuterated counterparts.

16 pages, 6 figures, 5 tables. Accepted for publication in Monthly Notices of the Royal Astronomical Society Main Journal

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• JOYS: The [D/H] abundance derived from protostellar outflows across the Galactic disk measured with JWST
• Interaction between the Supernova Remnant W44 and the Infrared Dark Cloud G034.77-00.55: shock induced star formation?
• On the Chemistry of the Young Massive Protostellar core NGC 2264 CMM3
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• On the Formation of Deuterated Methyl Formate in Hot Corinos