WISE J085510.83 - 071442.5 ( hereafter WISE 0855 - 0714 ) is the coldest known brown dwarf ( \sim 250 K ) and the fourth closest known system to the Sun ( 2.2 pc ) .
It has been previously detected only in the J band and two mid-IR bands .
To better measure its spectral energy distribution ( SED ) , we have performed deep imaging of WISE 0855 - 0714 in six optical and near-IR bands with Gemini Observatory , the Very Large Telescope , and the Hubble Space Telescope .
Five of the bands show detections , although one detection is marginal ( S/N \sim 3 ) .
We also have obtained two epochs of images with the Spitzer Space Telescope for use in refining the parallax of the brown dwarf .
By combining astrometry from this work and previous studies , we have derived a parallax of 0.449 \pm 0.008 \arcsec ( 2.23 \pm 0.04 pc ) .
We have compared our photometry for WISE 0855 - 0714 to data for known Y dwarfs and to the predictions of three suites of models by Saumon et al .
( 45 ) and Morley et al .
( 38 , 40 ) that are defined by the presence or absence of clouds and non-equilibrium chemistry .
Our estimates of Y - J and J - H for WISE 0855 - 0714 are redder than colors of other Y dwarfs , confirming a predicted reversal of near-IR colors to redder values at temperatures below 300–400 K. In color-magnitude diagrams , no single suite of models provides a clearly superior match to the sequence formed by WISE 0855 - 0714 and other Y dwarfs .
Instead , the best fitting model changes from one diagram to the next .
Similarly , all of the models have substantial differences from the SED of WISE 0855 - 0714 .
As a result , we are currently unable to constrain the presence of clouds or non-equilibrium chemistry in its atmosphere .