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 ∼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.
@article{arxiv.astro-ph/0503587,
title = {H-D Substitution in Interstellar Solid Methanol: A Key Route for D Enrichment},
author = {Akihiro Nagaoka and Naoki Watanabe and Akira Kouchi},
journal= {arXiv preprint arXiv:astro-ph/0503587},
year = {2009}
}