Japan Geoscience Union Meeting 2018

Presentation information

[EE] Oral

B (Biogeosciences) » B-AO Astrobiology & the Origin of Life

[B-AO01] Astrobiology

Tue. May 22, 2018 3:30 PM - 5:00 PM 102 (1F International Conference Hall, Makuhari Messe)

convener:Hikaru Yabuta(Hiroshima University, Department of Earth and Planetary Systems Science), Seiji Sugita(Department of Earth and Planetary Science, Graduate School of Science Sciece, The University of Tokyo), Misato Fukagawa(名古屋大学, 共同), Fujishima Kosuke(Tokyo Institute of Technology, Earth-Life Science Institute), Chairperson:Yabuta Hikaru(Hiroshima University), Sugita Seiji(東京大学大学院 理学系研究科)

3:55 PM - 4:10 PM

[BAO01-11] An Expanded Gas-Grain Model for Interstellar Glycine

*Taiki Suzuki1, Liton Majumdar2, Masatoshi Ohishi3, Masao Saito3, Tomoya Hirota3, Valentine Wakelam4 (1.National Institutes of Natural Sciences Astrobiology Center, 2.Jet Propulsion Laboratory, NASA, 3.National Astronomical Observatory of Japan, 4.Bordeaux University)

Keywords:Interstellar Chemistry, Chemical Evolution, Glycine

The study of the chemical evolution of glycine in the interstellar medium is one of challenging topics in astrochemistry. Here, we present the chemical modeling of glycine in hot cores using the state-of-the-art three-phase chemical model NAUTILUS, which is focused on the latest glycine chemistry. For the formation process of glycine on the grain surface, we obtained consistent results with previous studies that glycine would be formed via the reactions of COOH with CH2NH2. However, we will report three important findings regarding the chemical evolution of interstellar glycine. First, with the experimentally obtained binding energy from the temperature programmed thermal desorption (TPD) experiment, large part of glycine was destroyed through the grain surface reactions with NH or CH3O radicals before it fully evaporates. As a result, the formation process in the gas phase is more important than thermal evaporation from grains. If this is the case, NH2OH and CH3COOH rather than CH3NH2 and CH2NH would be the essential precursors to the gas phase glycine. Secondly, since the gas phase glycine will be quickly destroyed by positive ions or radicals, early evolutionary phase of the hot cores would be the preferable target for the future glycine surveys. Thirdly, we suggest the possibility that the suprathermal hydrogen atoms can strongly accelerate the formation of COOH radicals from CO2, resulting in the dramatical increase of formation rate of glycine on grains. The efficiency of this process should be investigated in detail by theoretical and experimental studies in the future.