SIMBAD references

2018ApJ...854L..27G - Astrophys. J., 854, L27-L27 (2018/February-3)

2MASS J13243553+6358281 is an early T-type planetary-mass object in the AB Doradus moving group.


Abstract (from CDS):

We present new radial velocity and trigonometric distance measurements indicating that the unusually red and photometrically variable T2 dwarf 2MASS J13243553+6358281 is a member of the young (∼150 Myr) AB Doradus moving group (ABDMG) based on its space velocity. We estimate its model-dependent mass in the range 11-12 MJup at the age of the ABDMG, and its trigonometric distance of 12.7 ± 1.5 pc makes it one of the nearest known isolated planetary-mass objects. The unusually red continuum of 2MASS J13243553+6358281 in the near-infrared was previously suspected to be caused by an unresolved L + T brown dwarf binary, although it was never observed with high spatial resolution imaging. This new evidence of youth suggests that a low surface gravity may be sufficient to explain this peculiar feature. Using the new parallax we find that its absolute J-band magnitude is ∼0.4 mag fainter than equivalent-type field brown dwarfs, suggesting that the binary hypothesis is unlikely. The fundamental properties of 2MASS J13243553+6358281 follow the spectral type sequence of other known high-likelihood members of the ABDMG. The effective temperature of 2MASS J13243553+6358281 provides the first precise constraint on the L/T transition at a known young age and indicates that it happens at a temperature of ∼1150 K at ∼150 Myr, compared to ∼1250 K for field brown dwarfs.

Abstract Copyright: © 2018. The American Astronomical Society. All rights reserved.

Journal keyword(s): brown dwarfs - methods: data analysis - proper motions - stars: individual: 2MASS J13243553+6358281 - stars: kinematics and dynamics

Simbad objects: 12

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