2017年4月

Detection of Submillimeter-wave [CI] Emission in Gaseous Debris Disks of 49 Ceti and beta Pictoris

ASTROPHYSICAL JOURNAL LETTERS
• Aya E. Higuchi
• ,
• Aki Sato
• ,
• Takashi Tsukagoshi
• ,
• Nami Sakai
• ,
• Kazunari Iwasaki
• ,
• Munetake Momose
• ,
• Hiroshi Kobayashi
• ,
• Daisuke Ishihara
• ,
• Sakae Watanabe
• ,
• Hidehiro Kaneda
• ,
• Satoshi Yamamoto

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DOI
10.3847/2041-8213/aa67f4

IOP PUBLISHING LTD

We have detected [C I] P-3(1)-P-3(0) emissions in the gaseous debris disks of 49 Ceti and beta Pictoris with the 10 m telescope of the Atacama Submillimeter Telescope Experiment, which is the first detection of such emissions. The line profiles of [C I] are found to resemble those of CO(J = 3-2) observed with the same telescope and the Atacama Large Millimeter/submillimeter Array. This result suggests that atomic carbon (C) coexists with CO in the debris disks. and is likely formed by the photodissociation of CO. Assuming an optically thin [C I] emission with the excitation temperature ranging from 30 to 100. K, the column density of C is evaluated to be (2.2 +/- 0.2). x. 10(17) and (2.5 +/- 0.7). x. 10(16). cm(-2) for 49 Ceti and beta Pictoris, respectively. The C/CO column density ratio is thus derived to be 54 +/- 19 and 69 +/- 42 for 49 Ceti and beta Pictoris, respectively. These ratios are higher than those of molecular clouds and diffuse clouds by an order of magnitude. The unusually high ratios of C to CO are likely attributed to a lack of H-2 molecules needed to reproduce CO molecules efficiently from C. This result implies a small number of H-2 molecules in the gas disk,. i.e., there is an appreciable contribution of secondary gas from dust grains.

Web of Science ® 被引用回数 : 12

リンク情報
DOI
https://doi.org/10.3847/2041-8213/aa67f4
arXiv
http://arxiv.org/abs/arXiv:1703.06661
Web of Science