1306.1887 (Michihiro Takami et al.)

High-Contrast Near-Infrared Imaging Polarimetry of the Protoplanetary Disk around RY Tau    [PDF]

Michihiro Takami, Jennifer L. Karr, Jun Hashimoto, Hyosun Kim, John Wisnewski, Thomas Henning, Carol A. Grady, Ryo Kandori, Klaus W. Hodapp, Tomoyuki Kudo, Nobuhiko Kusakabe, Mei-Yin Chou, Yoichi Itoh, Munetake Momose, Satoshi Mayama, Thayne Currie, Katherine B. Follette, Jungmi Kwon, Lyu Abe, Wolfgang Brandner, Timothy D. Brandt, Joseph Carson, Sebastian E. Egner, Markus Feldt, Olivier Guyon, Yutaka Hayano, Masahiko Hayashi, Saeko Hayashi, Miki Ishii, Masanori Iye, Markus Janson, Gillian R. Knapp, Masayuki Kuzuhara, Michael W. McElwain, Taro Matsuo, Shoken Miyama, Jun-Ichi Morino, Amaya Moro-Martin, Tetsuo Nishimura, Tae-Soo Pyo, Eugene Serabyn, Hiroshi Suto, Ryuji Suzuki, Naruhisa Takato, Hiroshi Terada, Christian Thalmann, Daigo Tomono, Edwin L. Turner, Makoto Watanabe, Toru Yamada, Hideki Takami, Tomonori Usuda, Motohide Tamura

We present near-infrared coronagraphic imaging polarimetry of RY Tau. The scattered light in the circumstellar environment was imaged at H-band at a high resolution (~0".05) for the first time, using Subaru-HiCIAO. The observed polarized intensity (PI) distribution shows a butterfly-like distribution of bright emission with an angular scale similar to the disk observed at millimeter wavelengths. This distribution is offset toward the blueshifted jet, indicating the presence of a geometrically thick disk or a remnant envelope, and therefore the earliest stage of the Class II evolutionary phase. We perform comparisons between the observed PI distribution and disk models with: (1) full radiative transfer code, using the spectral energy distribution (SED) to constrain the disk parameters; and (2) monochromatic simulations of scattered light which explore a wide range of parameters space to constrain the disk and dust parameters. We show that these models cannot consistently explain the observed PI distribution, SED, and the viewing angle inferred by millimeter interferometry. We suggest that the scattered light in the near-infrared is associated with an optically thin and geometrically thick layer above the disk surface, with the surface responsible for the infrared SED. Half of the scattered light and thermal radiation in this layer illuminates the disk surface, and this process may significantly affect the thermal structure of the disk.

View original: http://arxiv.org/abs/1306.1887