We report the discovery of a wide ( \sim 1400 AU projected separation ) , common proper motion companion to the nearby M dwarf LHS 2803 ( PSO J207.0300 - 13.7422 ) .
This object was discovered during our census of the local T dwarf population using Pan-STARRS1 and 2MASS data .
Using IRTF/SpeX near-infrared spectroscopy , we classify the secondary to be spectral type T5.5 .
University of Hawai ‘ i 2.2m/SNIFS optical spectroscopy indicates that the primary has a spectral type of M4.5 , with approximately solar metallicity and no measurable H \alpha emission .
We use this lack of activity to set a lower age limit for the system of 3.5 Gyr .
Using a comparison with chance alignments of brown dwarfs and nearby stars , we conclude that the two objects are unlikely to be a chance association .
The primary ’ s photometric distance of 21 pc and its proper motion implies thin disk kinematics .
Based on these kinematics and its metallicity , we set an upper age limit for the system of 10 Gyr .
Evolutionary model calculations suggest that the secondary has a mass of 72 \pm ^ { 4 } _ { 7 } M _ { Jup } , temperature of 1120 \pm 80 K , and \log g =5.4 \pm 0.1 dex .
Model atmosphere fitting to the near-IR spectrum gives similar physical parameters of 1100 K and \log g =5.0 .