Chemical evolution of sulfur-bearing molecules in interstellar molecular clouds

2016 Fiscal Year Final Research Report

• Project/Area Number: 26707030
• Research Category: Grant-in-Aid for Young Scientists (A)
• Allocation Type: Partial Multi-year Fund
• Research Field: Geochemistry/Cosmochemistry
• Research Institution: Hokkaido University
• Principal Investigator: OBA YASUHIRO 北海道大学, 低温科学研究所, 助教 (00507535)
• Project Period (FY): 2014-04-01 – 2017-03-31
• Keywords: 化学進化 / 硫黄 / 重水素濃集

Outline of Final Research Achievements

In the present study, laboratory experiments on the chemical evolution of the representative sulfur-bearing interstellar molecules, hydrogen sulfide (H2S), were performed under the interstellar conditions (low T, P). H2S was found to react with H and D atoms on the substrate at low temperatures. When it reacts with H atoms, the H of H2S is abstracted to form HS radicals, which are expected to react with other H atoms to result in the formation of H2S again. However, the H2S abundance was getting smaller with H atom exposure times. This is probably due to the chemical desorption of H2S by using the heat of formation of H2S.
When H2S reacted with D atoms under the similar conditions, the formation of its deuterated counterparts (HDS and D2S) was confirmed. It is strongly expected that the high degree of H2S deuteration levels in interstellar and cometary H2S is induced by surface reactions on interstellar grains.

Free Research Field

宇宙地球化学