We present a new radial velocity measurement that , together with a trigonometric parallax , proper motion and signs of low gravity from the literature , confirms that SDSS J111010.01+011613.1 is a new T5.5 bona fide member of AB Doradus .
Fitting \lambda / \Delta \lambda \approx 6000 FIRE spectroscopy in the 1.20–1.33 \mu m region to BT-Settl atmosphere models yielded a radial velocity of 7.5 \pm 3.8 km s ^ { -1 } .
At such a young age ( 110–130 Myr ) , current evolution models predict a mass of \sim 10–12 M _ { \mathrm { Jup } } , thus placing SDSS J1110+0116 well into the planetary-mass regime .
We compare the fundamental properties of SDSS J1110+0116 with a sequence of seven recently identified M8–T5 brown dwarf bona fide or high-confidence candidate members of AB Doradus .
We also note that its near-infrared J - K color is redder than field T5–T6 brown dwarfs , however its absolute J -band magnitude is similar to them .
SDSS J1110+0116 is one of the few age-calibrated T dwarfs known to date , as well as one of the coolest bona fide members of a young moving group .