HST NICMOS Imaging of the Planetary-mass Companion to the Young Brown Dwarf 2MASSW J1207334–393254

Creators: Song, Inseok; Schneider, G.; Zuckerman, B.; Farihi, J.; Becklin, E. E.; Bessell, M. S.; Lowrance, P.; Macintosh, B. A.

Abstract

Multiband (0.9-1.6 μm) images of the TW Hydrae association (TWA) brown dwarf 2MASSW J1207334-393254 (also known as 2M 1207) and its candidate planetary-mass companion (2M 1207b) were obtained on 2004 August 28 and 2005 April 26 with HST NICMOS. The images from these two epochs unequivocally confirm the two objects as a common proper motion pair (16.0 σ confidence). A new measurement of the proper motion of 2M 1207 implies a distance to the system of 59 ± 7 pc and a projected separation of 46 ± 5 AU. The NICMOS and previously published VLT photometry of 2M 1207b, extending overall from 0.9 to 3.8 μm, are fully consistent with an object of a few Jupiter masses at the canonical age of a TWA member (~8 Myr) based on evolutionary models of young giant planets. These observations provide information on the physical nature of 2M 1207b and unambiguously establish that the first direct image of a planetary-mass companion in orbit around a self-luminous body, other than our Sun, has been secured.

Additional Information

© 2006 American Astronomical Society. Received 2005 August 25; accepted 2006 July 20. This research was supported by STScI through grant HST-GO-10176. Portions of this research were performed under the auspices of the US Department of Energy by the University of California, Lawrence Livermore National Laboratory under contract W-7405-ENG-48. We thank Michael Wenz (STScI) and Merle Reinhart (CSC) for their assistance in determining HST's absolute orientation error following the guide star acquisitions for each of our orbits. Our gratitude is extended to Al Schultz and Beth Perrillo (our contact scientist and program coordinator at STScI) for their assistance in implementing and scheduling our observations. We thank Richard Crowe for kindly obtaining the 2005 I-band data and Bob Shobbrook for the 2006 I-band image used in our proper-motion refinement. We thank the referee for pointing out to us the potential importance of differential atmospheric refraction in our 2005 I-band image. This work was supported by the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., on behalf of the international Gemini partnership of Argentina, Australia, Brazil, Canada, Chile, the United Kingdom, and the United States of America.

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