Through a previous analysis of multi-epoch astrometry from the Wide-field Infrared Survey Explorer ( WISE ) , I identified WISE J085510.83 - 071442.5 as a new high proper motion object .
By combining astrometry from WISE and the Spitzer Space Telescope , I have measured a proper motion of 8.1 \pm 0.1 \arcsec yr ^ { -1 } and a parallax of 0.454 \pm 0.045 \arcsec ( 2.20 ^ { +0.24 } _ { -0.20 } pc ) for WISE J085510.83 - 071442.5 , giving it the third highest proper motion and the fourth largest parallax of any known star or brown dwarf .
It is also the coldest known brown dwarf based on its absolute magnitude at 4.5 µm and its color in [ 3.6 ] - [ 4.5 ] .
By comparing M _ { 4.5 } with the values predicted by theoretical evolutionary models , I estimate an effective temperature of 225–260 K and a mass of 3–10 M _ { Jup } for the age range of 1–10 Gyr that encompasses most nearby stars .