We explore and discount the hypothesis that the strong , continual H \alpha -emitting T dwarf 2MASS J12373919+6526148 can be explained as a young , low gravity , very low mass brown dwarf .
The source is already known to have a marginally-fainter absolute magnitude than similar T dwarfs with trigonometric parallax measurements , and has a tangential velocity consistent with old disk kinematics .
Applying the technique of Burgasser , Burrows & Kirkpatrick on new near infrared spectroscopy for this source , estimates of its T _ { eff } , \log { g } and metallicity ( [ M/H ] ) are obtained .
2M 1237+6526 has a T _ { eff } \approx 800-850 K. If [ M/H ] is solar , \log { g } is as high as \sim 5.5 ( cgs ) and this source is older than 10 Gyr .
We find a more plausible scenario to be a modestly subsolar metallicity ( [ M/H ] = -0.2 ) and moderate \log { g } \sim 5.0 , implying an age older than 2 Gyr and a mass greater than 0.035 M _ { \sun } .
The alternative explanation of the unique emission of this source , involving an interacting , close , double degenerate system , should be investigated further .
Indeed , there is some evidence of a T _ { eff } < 500 K companion to 2M 1237+6526 on the basis of a possible Spitzer~ { } IRAC [ 3.6 ] – [ 4.5 ] color excess .
This excess may , however , be caused by a subsolar metallicity .