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arXiv · 1512.05440

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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Abstract

We report the first detection of a gap and a ring in 336 GHz dust continuum emission from the protoplanetary disk around TW Hya, using the Atacama Large Millimeter/Submillimeter Array (ALMA). The gap and ring are located at around 25 and 41 au from the central star, respectively, and are associated with the CO snow line at ~30 au. The gap has a radial width of less than 15 au and a mass deficit of more than 23%, taking into account that the observations are limited to an angular resolution of ~15 au. In addition, the 13CO and C18O J = 3 - 2 lines show a decrement in CO line emission throughout the disk, down to ~10 au, indicating a freeze-out of gas-phase CO onto grain surfaces and possible subsequent surface reactions to form larger molecules. The observed gap could be caused by gravitational interaction between the disk gas and a planet with a mass less than super-Neptune (2M_{Neptune}), or could be the result of the destruction of large dust aggregates due to the sintering of CO ice.

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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. 2016-02-26. ALMA Observations of a Gap and a Ring in the Protoplanetary Disk around TW Hya. https://doi.org/10.3847/2041-8205%2F819%2F1%2Fl7

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