Dynamical masses for the nearest brown dwarf binary: Epsilon Indi Ba, Bb
Abstract
We present preliminary astrometric results for the closest known brown dwarf binary to the Sun: Epsilon Indi Ba, Bb at a distance of 3.626 pc. Via ongoing monitoring of the relative separation of the two brown dwarfs (spectral types T1 and T6) with the VLT NACO near-IR adaptive optics system since June 2004, we obtain a model-independent dynamical total mass for the system of 121 MJup, some 60% larger than the one obtained by McCaughrean et al. (2004), implying that the system may be as old as 5 Gyr. We have also been monitoring the absolute astrometric motions of the system using the VLT FORS2 optical imager since August 2005 to determine the individual masses. We predict a periastron passage in early 2010, by which time the system mass will be constrained to < 1 MJup and we will be able to determine the individual masses accurately in a dynamical, model-independent manner.
Cite
@article{arxiv.0811.0588,
title = {Dynamical masses for the nearest brown dwarf binary: Epsilon Indi Ba, Bb},
author = {C. V. Cardoso and M. J. McCaughrean and R. R. King and L. M. Close and R. -D. Scholz and R. Lenzen and W. Brandner and N. Lodieu and H. Zinnecker},
journal= {arXiv preprint arXiv:0811.0588},
year = {2009}
}
Comments
To appear in proceedings of Cool Stars XV, 5 pages, 2 figures, slightly expanded version