2M0838+15 is a triple brown dwarf
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! style="text-align: center; background-color: #FFFFC0;" colspan="2" | Observation dataEpoch J2000      Equinox J2000
! style="text-align:left" | Constellation
! style="text-align:left" | Right ascension
! style="text-align:left" | Declination
! style="background-color: #FFFFC0; text-align: center;" colspan="2"| Characteristics
! style="text-align:left" | Evolutionary stage
! style="text-align:left" | Spectral type
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! style="background-color: #FFFFC0; text-align: center;" colspan="2" | Position (relative to 2M0838+15A)
! style="background-color: #FFFFC0; text-align: center;" colspan="2" | Position (relative to 2M0838+15B)
2M0838+15 (also known as 2MASS J08381155+1511155) is a triple brown dwarf with all three components being T dwarfs. It was the first fully resolved triple T-type brown dwarf system that was discovered.
Description.
2M0838+15 was discovered in a cross-match of 2MASS and WISE as a possible T6-T7 dwarf. 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 MJ, and for an age of 300 million years the researchers estimate masses of 21+19+17 MJ. 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.
See also.
other triple brown dwarfs:
References.
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