Near-Infrared Polarimetry of the GG Tauri A Binary System

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

Published 2015-08-31Version 1

A high angular resolution near-infrared polarized-intensity image of the GG Tau A binary system was obtained with the Subaru Telescope. The image shows the circumbinary disk scattering the light from the central binary. The azimuthal profile of the polarized intensity of the circumbinary disk is roughly reproduced by a simple disk model with the Henyey-Greenstein function and the Rayleigh function, indicating small dust grains at the surface of the disk. Combined with a previous observation of the circumbinary disk, our image indicates that the gap structure in the circumbinary disk orbits anti-clockwise, while material in the disk orbit clockwise. We propose a shadow of material located between the central binary and the circumbinary disk. The separations and position angles of the stellar components of the binary in the past 20 years are consistent with the binary orbit with a = 33.4 AU and e = 0.34.