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タイトル	en Methane Formation Efficiency on Icy Grains: Role of Adsorption States
作成者	en Tsuge, Masashi NRID 1000060454211 en Molpeceres, Germán en Aikawa, Yuri en Watanabe, Naoki NRID 1000050271531
アクセス権	metadata only access
権利情報	https://creativecommons.org/licenses/by/4.0/ en Creative Commons Attribution 4.0 International
主題	NDC 440
内容注記	Abstract en Methane (CH4) is one of the major components of the icy mantle of cosmic dust prevalent in cold, dense regions of interstellar media, playing an important role in the synthesis of complex organic molecules and prebiotic molecules. Solid CH4 is considered to be formed via the successive hydrogenation of C atoms accreting onto dust: C + 4H → CH4. However, most astrochemical models assume this reaction on the ice mantles of dust to be barrierless and efficient, without considering the states of adsorption. Recently, we found that C atoms exist in either the physisorbed or chemisorbed state on compact amorphous solid water, which is analogous to an interstellar ice mantle. These distinct adsorption states considerably affect the hydrogenation reactivity of the C atom. Herein, we elucidate the reactivities of physisorbed and chemisorbed C atoms with H atoms via sequential deposition and codeposition processes. The results indicate that only physisorbed C atoms can produce CH4 on ice. Combining this finding with a previous estimate for the fraction of physisorbed C atoms on ice, we determined the upper limit for the conversion of C atoms into CH4 to be 30%.
出版者	en American Astronomical Society
日付	Issued2024-09-20
言語	und
資源タイプ	journal article
出版タイプ	NA
資源識別子	HDL http://hdl.handle.net/2115/93086
関連	isIdenticalTo DOI https://doi.org/10.3847/1538-4357/ad656a
収録誌情報	PISSN 0004-637X EISSN 1538-4357 en The Astrophysical Journal 巻973 号2 開始ページ80
コンテンツ更新日時	2024-09-28