The Asymmetric Thermal Emission of Protoplanetary Disk Surrounding HD 142527 Seen by Subaru/COMICS

Mid-infrared (MIR) images of the Herbig Ae star HD 142527 were obtained at 18.8 and 24.5 μm with the Subaru/COMICS. Bright extended arc-like emission (outer disk) is recognized at r = 0. 85 together with a strong central source (inner disk) and a gap around r = 0. 6 in the both images. Thermal emission of the eastern side is much brighter than that of the western side in the MIR. We estimate the dust size as a few μm from the observed color of the extended emission and the distance from the star. The dust temperature T and the optical depth τ of the MIR emitting dust are also derived from the two images as T = 82±1 K, τ = 0.052±0.001 for the eastern side and T = 85±3 K, τ = 0.018±0.001 for the western side. The observed asymmetry in the brightness can be attributed to the difference in the optical depth of the MIR emitting dust. To account for the present observations, we propose an inclined disk model, in which the outer Based on data collected at Subaru Telescope, which is operated by the National Astronomical Observatory of Japan. Department of Astronomy, School of Science, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan; [email protected], [email protected], [email protected]. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510, Japan; [email protected], [email protected]. Subaru Telescope, National Astronomical Observatory of Japan, 650 North A’ohoku Place, Hilo, HI 96720; [email protected], [email protected]. Spitzer Science Center, California Institute of Technology, Mail Code 220-6, Pasadena, CA 91125, U.S.A.; [email protected]. 6 Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan. Institute of Astrophysics and Planetary Sciences, Ibaraki University, Bunkyo 2-1-1, Mito, Ibaraki 3108512, Japan; [email protected]. Institute of Astronomy, University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-0015, Japan; [email protected], [email protected].