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Imaging of a Transitional Disk Gap in Reflected Light: Indications of Planet Formation Around the Young Solar Analog LkCa 15

Thalmann, C. and Serabyn, E. (2010) Imaging of a Transitional Disk Gap in Reflected Light: Indications of Planet Formation Around the Young Solar Analog LkCa 15. Astrophysical Journal Letters, 718 (2). L87-L91. ISSN 2041-8205.

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We present H- and K s-band imaging data resolving the gap in the transitional disk around LkCa 15, revealing the surrounding nebulosity. We detect sharp elliptical contours delimiting the nebulosity on the inside as well as the outside, consistent with the shape, size, ellipticity, and orientation of starlight reflected from the far-side disk wall, whereas the near-side wall is shielded from view by the disk's optically thick bulk. We note that forward scattering of starlight on the near-side disk surface could provide an alternate interpretation of the nebulosity. In either case, this discovery provides confirmation of the disk geometry that has been proposed to explain the spectral energy distributions of such systems, comprising an optically thick disk with an inner truncation radius of ~46 AU enclosing a largely evacuated gap. Our data show an offset of the nebulosity contours along the major axis, likely corresponding to a physical pericenter offset of the disk gap. This reinforces the leading theory that dynamical clearing by at least one orbiting body is the cause of the gap. Based on evolutionary models, our high-contrast imagery imposes an upper limit of 21 M Jup on companions at separations outside of 0".1 and of 13 M_(Jup) outside of 0".2. Thus, we find that a planetary system around LkCa 15 is the most likely explanation for the disk architecture.

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Additional Information:© 2010 American Astronomical Society. Received 2010 April 12; accepted 2010 June 1; published 2010 July 8. We thank Cornelis P. Dullemond and Dmitry Semenov for helpful discussion, and David Lafreni`ere for generously providing us with the source code for his LOCI algorithm. This work is partly supported by a Grant-in-Aid for Science Research in a Priority Area from MEXT and by the Mitsubishi Foundation. J.P.W. and M.W.M. acknowledge support from NSF Astronomy & Astrophysics Postdoctoral Fellowships AST 08-02230 and AST-0901967, respectively. E.L.T. gratefully acknowledges support from a Princeton University Global Collaborative Research Fund grant and the World Premier International Research Center Initiative (WPI Initiative), MEXT, Japan. Part of this work was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA. J.P.W. also acknowledges funding from a Chr´etien International Research Grant. Facilities: Subaru (HiCIAO, AO188), VLT:Yepun (NACO)
Funding AgencyGrant Number
Ministry of Education, Culture, Sports, Science and Technology (MEXT), JapanUNSPECIFIED
Mitsubishi FoundationUNSPECIFIED
NSFAST 08-02230
Princeton University Global Collaborative Research FundUNSPECIFIED
World Premier International Research Center Initiative (WPI Initiative)UNSPECIFIED
Chrétien International Research GrantUNSPECIFIED
Subject Keywords:circumstellar matter; planetary systems; stars: individual (LkCa 15); stars: pre-main sequence; techniques: high angular resolution
Issue or Number:2
Record Number:CaltechAUTHORS:20100831-152213449
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Official Citation:C. Thalmann et al 2010 ApJ 718 L87 doi: 10.1088/2041-8205/718/2/L87
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:19750
Deposited By: Jason Perez
Deposited On:03 Sep 2010 18:09
Last Modified:03 Oct 2019 02:01

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