2MASS J08381155+1511155

2M0838+15 was discovered in a cross-match of 2MASS and WISE as a possible T6-T7 dwarf.^[3] An unresolved spectrum with NASA IRTF was obtained. Follow-up imaging observations with Keck NIRC2 showed that this system is a triple system. Follow-up observations with Keck/OSIRIS resulted in resolved spectrum of the A and the BC components. The spectrum for component A matches a T3 ±1 spectral type. The BC spectrum matches a combined spectral type, which is composed of T3 ± 1 (B), and T4.5 ± 1 (C). Follow-up imaging showed that the triple has a common proper motion. Components BC have a relative small separation of around 2.5 AU and should have an orbital period of around 12 or 21 years. This could mean that in the future the masses can be measured for both components by using the dynamical mass method. For an age of 3 billion years the researchers estimate masses of 63+58+52 M_J, and for an age of 300 million years the researchers estimate masses of 21+19+17 M_J. The researchers find that for an age of 3 billion years the system would have a gravitational binding energy of about 20 × 10⁴¹ erg. This would be high enough for the system to survive a dynamical ejection from a star-forming region. For an age of 300 million years, the gravitational binding energy is about 1.6 × 10⁴¹ erg, which would make it a rare weakly bound triple. The researchers conclude that it is less likely that 2M0838+15 is young.^[1]

other triple brown dwarfs:

• DENIS-P J020529.0−115925
• 2M1510 includes eclipsing binary pair
• VHS J1256–1257
• 2MASS J0920+3517