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Published December 20, 2004 | Published + Submitted
Journal Article Open

Initial Results from the Palomar Adaptive Optics Survey of Young Solar‐Type Stars: A Brown Dwarf and Three Stellar Companions


We present first results from the Palomar Adaptive Optics Survey of Young Stars conducted at the Hale 5 m telescope. Through direct imaging we have discovered a brown dwarf and two low-mass stellar companions to the young solar-type stars HD 49197, HD 129333 (EK Dra), and V522 Per and confirmed a previously suspected companion to RX J0329.1+0118 (Sterzik et al.), at respective separations of 0."95 (43 AU), 0."74 (25 AU), 2."09 (400 AU), and 3."78 (380 AU). Physical association of each binary system is established through common proper motion and/or low-resolution infrared spectroscopy. Based on the companion spectral types, we estimate their masses at 0.06, 0.20, 0.13, and 0.20 M_☉, respectively. From analysis of our imaging data combined with archival radial velocity data, we find that the spatially resolved companion to HD 129333 is potentially identical to the previously identified spectroscopic companion to this star (Duquennoy & Mayor). However, a discrepancy with the absolute magnitude suggests that the two companions could also be distinct, with the resolved one being the outermost component of a triple system. The brown dwarf HD 49197B is a new member of a growing list of directly imaged substellar companions at 10-1000 AU separations from main-sequence stars, indicating that such brown dwarfs may be more common than initially speculated.

Additional Information

© 2004 American Astronomical Society. Received 2004 May 20. Accepted 2004 August 27. We would like to thank Richard Dekany and Mitchell Troy for sharing with us their expertise of the Palomar AO system, Rick Burress and Jeff Hickey for assistance with PHARO, Randy Campbell, Paola Amico, and David Le Mignant for their guidance in using Keck AO, Keith Matthews and Dave Thompson for help with NIRC2, and our telescope operators Jean Mueller at the Palomar 5 m telescope and Chuck Sorenson at the Keck II telescope. We are grateful to Tom Hayward, Stephen Eikenberry, and Matthew Britton for sharing with us their ideas on AO data reduction and PSF subtraction. We thank Russel White for insightful discussions on spectroscopic binaries and for a critical review of the manuscript and the referee for detailed suggestions on chance alignment probabilities. We thank George Carlson and Donna Kirkpatrick of the Ahmanson Foundation Star Plates Archival Project for giving us access to the Mount Wilson spectroscopic survey plates. This publication makes use of data products from the Two Micron All Sky Survey, which is a joint project of the University of Massachusetts and the IPAC/California Institute of Technology, funded by NASA and the NSF. Use of the FEPS Team database has proven invaluable throughout the course of our survey. We thank John Carpenter for building and maintaining the database. Finally, the authors wish to extend special thanks to those of Hawaiian ancestry on whose sacred mountain of Mauna Kea we are privileged to be guests. Without their generous hospitality, some of the observations presented herein would not have been possible.

Attached Files

Published - Metchev_2004_ApJ_617_1330.pdf

Submitted - 0408528.pdf


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