A Caltech Library Service

Evidence of Orbital Motion in the Binary Brown Dwarf Kelu‐1AB

Gelino, Christopher R. and Kulkarni, S. R. and Stephens, Denise C. (2006) Evidence of Orbital Motion in the Binary Brown Dwarf Kelu‐1AB. Publications of the Astronomical Society of the Pacific, 118 (4). pp. 611-616. ISSN 0004-6280. doi:10.1086/502985.

PDF - Published Version
See Usage Policy.


Use this Persistent URL to link to this item:


We have resolved Kelu‐1 into a binary system with a separation of 290 mas using the Laser Guide Star Adaptive Optics system on the Keck II telescope. We have also reanalyzed a 1998 HST observation of Kelu‐1 and find that the observed PSF is best fit by a binary object separated by 45 mas. Observations at multiple epochs confirm that the two objects share a common proper motion and clearly demonstrate the first evidence of orbital motion. Kelu‐1B is fainter than Kelu‐1A by 0.39±0.01 mag in the K' filter and 0.50±0.01 mag in the H filter. We derive spectral types of L2±1 and L3.5±1 for Kelu-1A and B, respectively. The separation of flux into the two components rectifies Kelu‐1’s overluminosity problem, which has been known for quite some time. Given the available data, we are able to constrain the inclination of the system to >81° and the orbital period to 40 yr.

Item Type:Article
Related URLs:
URLURL TypeDescription
Kulkarni, S. R.0000-0001-5390-8563
Additional Information:© 2006. The Astronomical Society of the Pacific. Received 2005 September 19; accepted 2006 January 31; published 2006 April 27. The authors wish to thank the Keck LGSAO Team for their hard work in creating such a superb system. We also thank S. Wiktorowicz, D. Kirkpatrick, and N. Siegler (the referee) for useful discussions, as well as M. B. Stumpf, W. Brandner, and Th. Henning for informing us of the 2005 HST observation of Kelu‐1 through Protostars and Planets V poster 8571. This research has benefited from the M, L, and T dwarf compendium housed at and maintained by Chris Gelino, Davy Kirkpatrick, and Adam Burgasser. The HST M5 calibration data and Kelu‐1 images were obtained from the HST data archive at the Space Telescope Science Institute. STScI is operated by the Association of Universities for Research in Astronomy, Inc. under NASA contract NAS 5‐26555. The principle data presented here were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and NASA. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Mauna Kea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain.
Funding AgencyGrant Number
Space Telescope Science InstituteUNSPECIFIED
NASANAS 5‐26555
W. M. Keck FoundationUNSPECIFIED
Issue or Number:4
Record Number:CaltechAUTHORS:20090918-101012628
Persistent URL:
Official Citation:Evidence of Orbital Motion in the Binary Brown Dwarf Kelu‐1AB Christopher R. Gelino, S. R. Kulkarni, and Denise C. Stephens Publications of the Astronomical Society of the Pacific 2006 118:842, 611-616
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:15959
Deposited By: George Porter
Deposited On:22 Sep 2009 19:07
Last Modified:08 Nov 2021 23:23

Repository Staff Only: item control page