[P-PS04] [EJ] アルマによる惑星科学の新展開

[PPS04-P09] デブリ円盤​の[CI](³P₁-³P₀)輝線放射の検出

*樋口 あや¹、佐藤 愛樹²、塚越 崇²、坂井 南美¹、百瀬 宗武²、小林 浩³、石原 大助³、渡邊 華³、金田 英宏³、岩﨑 一成⁴、山本 智⁵ (1.理化学研究所、2.茨城大学、3.名古屋大学、4.同志社大学、5.東京大学)

キーワード：デブリ円盤

We have detected the [C I]³P₁–³P₀ emission in the gaseous debris disks, 49 Ceti and β Pictoris, with the Atacama Submillimeter Telescope Experiment (ASTE). The line profiles of [C I] is found to be those of CO(J=3–2) observed with the same telescope as well as the Atacama Large Millimeter/submillimeter Array (ALMA). This result suggests that the atomic carbon (C) coexists with CO in the debris disks, and is likely formed by photodissociation of CO. The C/CO column density ratio is thus derived to be 54±19 to 69±42 for 49 Ceti and β Pictoris, respectively. These ratios are higher than those of protoplanetary disks, molecular clouds, and diffuse clouds by an order of magnitude. From the result, we suggest that the origin of a large amount of [C I] in the debris disk would likely be a small amount of the H₂ molecule in the gas disk. This implies a significant contribution of the secondary gas coming out from dust grains.