Japan Geoscience Union Meeting 2023

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[E] Oral

M (Multidisciplinary and Interdisciplinary) » M-IS Intersection

[M-IS03] Astrobiology

Sun. May 21, 2023 1:45 PM - 3:15 PM 105 (International Conference Hall, Makuhari Messe)

convener:Kosuke Fujishima(Tokyo Institute of Technology, Earth-Life Science Institute), Seiji Sugita(Department of Earth and Planetary Science, Graduate School of Science Sciece, The University of Tokyo), Misato Fukagawa(National Astronomical Observatory of Japan), Yohey Suzuki(Graduate School of Science, The University of Tokyo), Chairperson:Misato Fukagawa(National Astronomical Observatory of Japan), Kosuke Fujishima(Tokyo Institute of Technology, Earth-Life Science Institute)

2:05 PM - 2:20 PM

[MIS03-02] Constraints on carbon isotope ratios in a planetary nursery: to understand the behavior of carbon

*Tomohiro Yoshida1, Hideko Nomura1, Takashi Tsukagoshi2, Kenji Furuya3, Seokho Lee4, Richard Teague5, Karin Öberg6 (1.NAOJ/SOKENDAI, 2.Ashikaga University, 3.NAOJ, 4.KASI, 5.MIT, 6.CfA/Harvard)

Keywords:planet formation, exoplanet, protoplanetary disk, isotope, carbon, ALMA

To understand the origin of life ultimately, it is necessary to reveal the environment of planetary systems as a first steps. In this talk, we focus on the behavior of carbon. Carbon is a major element in the interstellar medium, and an ingredient of organic molecules. Meanwhile, planetary systems are formed in protoplanetary disks by coagulation of dust particles and capturing gas. To reveal the carbon behavior in disks, it is useful to use its isotope ratio, 12C/13C, in carbon-bearing molecules since the ratio may reflect the environments of the molecular formation. We present new analysis of 12CN/13CN in a protoplanetary disks around a classical T Tauri star, TW Hya, using the Atacama Large Millimeter / sub-millimeter Array (ALMA) archival data. The 12CN/13CN ratio is lower than the local interstellar value, and shows a potential radial variation. By comparing previous measurements of 12CO/13CO and H12CN/H13CN, it is suggested that the gas-phase in the disk is significantly carbon rich with respect to oxygen. This might be results of depletion of CO and other species during the disk evolution. The removed CO from gas would be incorporated to ice on dust grains, making more complex molecules including CO2 and organic molecules.