Dynamical masses for the nearest brown dwarf binary: ε Indi Ba,b

Abstract

Zentrum fűr Astronomie Heidelberg, 8 UCLA, Binary brown dwarfs are important because their dynamical masses can be determined in a model-independent way. If a main sequence star is also involved, the age and metallicity for the system can be determined, making it possible to break the sub-stellar mass-age degeneracy. The most suitable benchmark system for intermediate age T dwarfs is ε Indi Ba,b, two T dwarfs (spectral types T1 and T6; McCaughrean et al. (2004)) orbiting a K4.5V star, ε Indi A, at a projected separation of 1460AU. At a distance of 3.6224pc (HIPPARCOS distance to ε Indi A; van Leeuwen (2007)), these are the closest brown dwarfs to the Earth, and thus both components are bright and the system is well-resolved. The system has been monitored astrometrically with NACO and FORS2 on the VLT since June 2004 and August 2005, respectively, in order to determine the system and individual masses independent of evolutionary models. We have obtained a preliminary system mass of 121±1MJup. We have also analysed optical/near-IR spectra (0.6−5.0μm at a resolution up to R∼5000; King et al. (2009)) allowing us to determine bolometric luminosities, compare and calibrate evolutionary and atmospheric models of T dwarfs at an age of 4-8Gyr.

Low-amplitude Solar-like Oscillations in the K5 V Star ϵ Indi A

“…Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Cardoso et al 2010;King et al 2010;Chen et al 2022). With the current determined dynamical masses of 66.92 ± 0.36 M Jup and 53.25 ± 0.29 M Jup for the brown dwarfs (Chen et al 2022), as well as an accurate distance, these are among the bestcharacterized brown dwarfs (Chen et al 2022).…”

Measuring the Initial Mass Function of Low Mass Stars and Brown Dwarfs

“…It is a T1+T6 close binary in a wide orbit around a K4.5V star at 3.6 pc. The 12 year T-dwarf binary orbit gives a dynamical system mass of 121 M Jup (Cardoso et al 2010), which given their luminosities indicates that both components are likely to be BDs. The positions of the components in colour-magnitude diagrams are not well described by current models (King et al 2010).…”