SIMP J013656.5+093347 Is Likely a Planetarymass Object in the CarinaNear Moving Group
Abstract
We report on the discovery that the nearby (∼6 pc) photometrically variable T2.5 dwarf SIMP J013656.5+093347 is a likely member of the ∼200 Myr old CarinaNear moving group with a probability of >99.9% based on its full kinematics. Our v\sin I measurement of 50.9 ± 0.8 km s^{1} combined with the known rotation period inferred from variability measurements provide a lower limit of 1.01 ± 0.02 {R}_{{Jup}} on the radius of SIMP 0136+0933, an independent verification that it must be younger than ∼950 Myr, according to evolution models. We estimate a field interloper probability of 0.2% based on the density of field T0T5 dwarfs. At the age of CarinaNear, SIMP 0136+0933 has an estimated mass of 12.7 ± 1.0 {M}_{{Jup}} and is predicted to have burned roughly half of its original deuterium. SIMP 0136+0933 is the closest known young moving group member to the Sun and is one of only a few known young T dwarfs, making it an important benchmark for understanding the atmospheres of young planetarymass objects.
 Publication:

The Astrophysical Journal
 Pub Date:
 May 2017
 DOI:
 10.3847/20418213/aa70e2
 arXiv:
 arXiv:1705.01625
 Bibcode:
 2017ApJ...841L...1G
 Keywords:

 brown dwarfs;
 planets and satellites: atmospheres;
 stars: individual: SIMP J013656.5+093347;
 stars: kinematics and dynamics;
 Astrophysics  Solar and Stellar Astrophysics;
 Astrophysics  Earth and Planetary Astrophysics
 EPrint:
 10 pages, 4 figures, 2 tables. Accepted for publication in the Astrophysical Journal Letters