ALMA Observations of a Gap and a Ring in the Protoplanetary Disk around TW Hya

Hideko Nomura, Takashi Tsukagoshi, Ryohei Kawabe, Daiki Ishimoto, Satoshi Okuzumi, Takayuki Muto, Kazuhiro D. Kanagawa, Shigeru Ida, Catherine Walsh, T. J. Millar, Xue-Ning Bai

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We report the first detection of a gap and a ring in dust continuum emission from the protoplanetary disk around TW Hya, using the Atacama Large Millimeter/Submillimeter Array. The gap and ring are located at 25 and 41 AU from the central star, respectively, and are associated with the CO snowline at ~ 30AU. The gap width and depth are 15AU at the maximum and 23% at the minimum, respectively, regarding that the observations are limited to an angular resolution of ~ 15AU. In addition, we detect a decrement in CO line emission down to ~ 10AU, indicating freeze-out of gas-phase CO onto grain surfaces and possible subsequent surface reactions to form larger molecules. According to theoretical studies, the gap could be caused by gravitational interaction between the disk gas and a planet with a mass less than super-Neptune (2 Neptune mass), or result from destruction of large dust aggregates due to the sintering of CO ice.
Original languageEnglish
Article numberL7
Number of pages7
JournalAstrophysical Journal Letters
Issue number1
Early online date24 Feb 2016
Publication statusPublished - 01 Mar 2016


  • astro-ph.EP

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