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

April 2006 • 2006PASP..118..611G

Authors • Gelino, Christopher R. • Kulkarni, S. R. • Stephens, Denise C.

Abstract • 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.

Links

• SIMBAD http://simbad.u-strasbg.fr/simbo.pl?bibcode=2006PASP..118..611G
• PDF https://iopscience.iop.org/article/10.1086/502985/pdf
• PREPRINT http://arxiv.org/abs/astro-ph/0508164
• DATA https://archive.stsci.edu/mastbibref.php?bibcode=2006PASP..118..611G
• DATA https://hst.esac.esa.int/ehst/#/pages/search;bibcode=2006PASP..118..611G
• ELECTR https://iopscience.iop.org/article/10.1086/502985
• SPIRES http://inspirehep.net/search?p=find+eprint+astro-ph/0508164