Discovery of solid HDO in grain mantles ?
نویسندگان
چکیده
The observation of deuterium fractionation in the molecular gas in hot cores is currently interpreted as evaporation of deuterium-rich molecules from the icy grain mantles where they accumulated during the cold, dense cloud core stage. The predicted enrichment in deuterium of the ices has never been observed. This work provides the rst detections of solid HDO in grain mantles. We nd column densities in the solid state of The estimated HDO]//H 2 O] ratios range from 810 ?4 in W33A to 10 ?2 in NGC7538IRS9. These values are comparable to the predictions by chemical models, and provide support for the assumption that the origin of the deu-terium enhancement in \hot cores" is evaporation from grain mantles.
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