SPIRAL STRUCTURE AND DIFFERENTIAL DUST SIZE DISTRIBUTION IN THE LkHα 330 DISK
- National Astronomical Observatory of Japan, 2-21-1, Osawa, Mitaka, Tokyo, 181-8588 (Japan)
- European Southern Observatory, Karl Schwarzschild Str 2, D-85748 Garching bei München (Germany)
- Institute of Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, Taipei, 10617, Taiwan (China)
- Univ. Grenoble Alpes, IPAG, F-38000 Grenoble, France. CNRS, IPAG, F-38000 Grenoble (France)
- Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)
- Max Planck Institute for Astronomy, Königstuhl 17, D-69117, Heidelberg (Germany)
- Space Science Institute, 4750 Walnut Street, Suite 205, Boulder, CO 80301 (United States)
- Department of Astronomy, Stockholm University, AlbaNova University Center, Stockholm, SE-106 91 (Sweden)
- Department of Physics and Astronomy, The University of Oklahoma, 440 W. Brooks Street, Norman, OK 73019 (United States)
- Subaru Telescope, National Astronomical Observatory of Japan, 650, North A’ohoku Place, Hilo, HI 96720 (United States)
- Astrobiology Center of NINS, 2-21-1, Osawa, Mitaka, Tokyo, 181-8588 (Japan)
- College of Science, Ibaraki University, 2-1-1, Bunkyo, Mito, Ibaraki, 310-8512 (Japan)
- Division of Liberal Arts, Kogakuin University, 1-24-2, Nishi-Shinjuku, Shinjuku-ku, Tokyo, 163-8677 (Japan)
- Department of Earth and Planetary Sciences, Tokyo Institute of Technology, 2-12-1, Ookayama, Meguro-ku, Tokyo 152-8551 (Japan)
Dust trapping accelerates the coagulation of dust particles, and, thus, it represents an initial step toward the formation of planetesimals. We report H-band (1.6 μm) linear polarimetric observations and 0.87 mm interferometric continuum observations toward a transitional disk around LkHα 330. As a result, a pair of spiral arms were detected in the H-band emission, and an asymmetric (potentially arm-like) structure was detected in the 0.87 mm continuum emission. We discuss the origin of the spiral arm and the asymmetric structure and suggest that a massive unseen planet is the most plausible explanation. The possibility of dust trapping and grain growth causing the asymmetric structure was also investigated through the opacity index (β) by plotting the observed spectral energy distribution slope between 0.87 mm from our Submillimeter Array observation and 1.3 mm from literature. The results imply that grains are indistinguishable from interstellar medium-like dust in the east side (β=2.0±0.5) but are much smaller in the west side β=0.7-0.4+0.5, indicating differential dust size distribution between the two sides of the disk. Combining the results of near-infrared and submillimeter observations, we conjecture that the spiral arms exist at the upper surface and an asymmetric structure resides in the disk interior. Future observations at centimeter wavelengths and differential polarization imaging in other bands (Y–K) with extreme AO imagers are required to understand how large dust grains form and to further explore the dust distribution in the disk.
- OSTI ID:
- 22862823
- Journal Information:
- The Astronomical Journal (Online), Vol. 152, Issue 6; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 1538-3881
- Country of Publication:
- United States
- Language:
- English
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