  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.
