A gap with a deficit of large grains in the protoplanetary disk around TW Hya

Journal Article · Sat Oct 01 04:00:00 EDT 2016 · Astrophysical Journal Letters

DOI:https://doi.org/10.3847/2041-8205/829/2/L35· OSTI ID:22868636

Tsukagoshi, Takashi ^[1]; Nomura, Hideko; Ishimoto, Daiki; Okuzumi, Satoshi ^[2]; Muto, Takayuki ^[3]; Kawabe, Ryohei ^[4]; Kanagawa, Kazuhiro D. ^[5]; Ida, Shigeru ^[6]; Walsh, Catherine ^[7]

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1. College of Science, Ibaraki University, Bunkyo 2-1-1, Mito, Ibaraki 310-8512 (Japan)
2. Department of Earth and Planetary Sciences, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro, Tokyo 152-8551 (Japan)
3. Division of Liberal Arts, Kogakuin University, 1-24-2 Nishi-Shinjuku, Shinjuku-ku, Tokyo 163-8677 (Japan)
4. National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan)
5. Institute of Physics and CASA*, Faculty of Mathematics and Physics, University of Szczecin, Wielkopolska 15, 70-451 Szczecin (Poland)
6. Earth-Life Science Institute, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro, Tokyo 152-8550 (Japan)
7. Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands)

We report ∼3 au resolution imaging observations of the protoplanetary disk around TW Hya at 145 and 233 GHz with the Atacama Large Millimeter/submillimeter Array. Our observations revealed two deep gaps (∼25%–50%) at 22 and 37 au and shallower gaps (a few percent) at 6, 28, and 44 au, as recently reported by Andrews et al. The central hole with a radius of ∼3 au was also marginally resolved. The most remarkable finding is that the spectral index α(R) between bands 4 and 6 peaks at the 22 au gap. The derived power-law index of the dust opacity β(R) is ∼1.7 at the 22 au gap and decreases toward the disk center to ∼0. The most prominent gap at 22 au could be caused by the gravitational interaction between the disk and an unseen planet with a mass of ≲1.5 M {sub Neptune}, although other origins may be possible. The planet-induced gap is supported by the fact that β(R) is enhanced at the 22 au gap, indicating a deficit of ∼millimeter-sized grains within the gap due to dust filtration by a planet.

• OSTI ID: 22868636
• Journal Information: Astrophysical Journal Letters, Journal Name: Astrophysical Journal Letters Journal Issue: 2 Vol. 829; ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
COSMIC DUST
GHZ RANGE
GRAVITATIONAL INTERACTIONS
IMAGES
MASS
OPACITY
PLANETS
PROTOPLANETS
RESOLUTION
STARS