[P-PS14] Origin and evolution of materials in space

[PPS14-04] ALMA observations of CO gas depletion in the protoplanetary disk around TW Hya

★Invited papers

*Hideko Nomura¹, Takashi Tsukagoshi², Ryohei Kawabe³, Daiki Ishimoto^4,1, Satoshi Okuzumi¹, Takayuki Muto⁵, Kazuhiro Kanagawa⁶, Shigeru Ida⁷, Catherine Walsh⁸, Tom J Millar⁹, Bai Xue-Ning¹⁰ (1.Department of Earth and Planetary Sciences, Tokyo Institute of Technology, 2.College of Science, Ibaraki University, 3.National Astronomical Observatory of Japan, 4.Department of Astronomy, Graduate School of Science, Kyoto University, 5.Division of Liberal Arts, Kogakuin University, 6.University of Szczecin, 7.Earth-Life Science Institute, Tokyo Institute of Technology, 8.Leiden Observatory, Leiden University, 9.Astrophysics Research Centre, School of Mathematics and Physics, Queen’s University Belfast, 10.Institute for Theory and Computation, Harvard-Smithsonian Center for Astrophysics)

Keywords:protoplanetary disks, CO line emission, formation of organic molecules

Protoplanetary disks are the natal place of planets and ALMA observations are now revealing the physical and chemical structure of planet forming regions in the disks. Understanding chemical components of gas, dust and ice in the disks is essential to investigate the origins of materials in the plants. In the talk, I shall report our recent ALMA Band 7 observations of CO isotopologue lines from the protoplanetary disk around TW Hya. The result shows a significant decrement in CO gas throughout the disk even inside the CO snowline, indicating freeze-out of gas-phase CO onto grain surfaces and possible subsequent surface reactions to form larger molecules. Complex organic molecules could be efficiently produced in the observed CO gas depleted regions.