Dynamical masses for the nearest brown dwarf binary: ε Indi ba, bb

C. V. Cardoso, M. J. Mccaughrean, R. R. King, L. M. Close, R. D. Scholz, R. Lenzen, W. Brandner, N. Lodieu, H. Zinnecker

Research output: Contribution to journalConference article

1 Scopus citations


We present preliminary astrometric results for the closest known brown dwarf binary to the Sun: ε Indi Ba, Bb at a distance of 3.626 pc. With ongoing monitoring of the relative separation of the two brown dwarfs (spectral types T1 and T6) with VLT NACO near-IR adaptive optics system since June 2004, we obtain a model-independent dynamical total mass for the system of 121 M jup, some 60% larger than the one obtained by McCaughrean et al., 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 M jup and we will be able to determine the individual masses accurately in a dynamical, model-independent manner.

Original languageEnglish (US)
Pages (from-to)509-512
Number of pages4
JournalAIP Conference Proceedings
StatePublished - Apr 23 2009
Event15th Cambridge Workshop on Cool Stars, Stellar Systems and the Sun - St. Andrews, United Kingdom
Duration: Jul 21 2008Jul 25 2008



  • Astrometry
  • Binaries
  • Brown dwarfs
  • Celestial mechanics
  • Visual

ASJC Scopus subject areas

  • Physics and Astronomy(all)

Cite this

Cardoso, C. V., Mccaughrean, M. J., King, R. R., Close, L. M., Scholz, R. D., Lenzen, R., Brandner, W., Lodieu, N., & Zinnecker, H. (2009). Dynamical masses for the nearest brown dwarf binary: ε Indi ba, bb. AIP Conference Proceedings, 1094, 509-512. https://doi.org/10.1063/1.3099160