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H-D Substitution in Interstellar Solid Methanol: A Key Route for D Enrichment

Akihiro Nagaoka·Naoki Watanabe·Akira Kouchi
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Abstract

Deuterium enrichment of interstellar methanol is reproduced experimentally for the first time via grain-surface H-D substitution in solid methanol at an atomic D/H ratio of 0.1. Although previous gas-grain models successfully reproduce the deuterium enrichments observed in interstellar methanol molecules (D/H of up to 0.4, compared to the cosmic ratio of $\sim 10^{-5})$, the models exclusively focus on deuterium fractionation resulting from the successive addition of atomic hydrogen/deuterium on CO. The mechanism proposed here represents a key route for deuterium enrichment that reproduces the high observed abundances of deuterated methanol, including multiple deuterations.

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Akihiro Nagaoka, Naoki Watanabe, Akira Kouchi. 2005-03-28. H-D Substitution in Interstellar Solid Methanol: A Key Route for D Enrichment. https://doi.org/10.1086/430304

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