Context :

Aims : We aim at measuring the near-infrared photometry , and deriving the mass , age , temperature , and surface gravity of WISE J085510.74 - 071442.5 ( J0855 - 0714 ) , which is the coolest known object beyond the Solar System as of today .

Methods : We use publicly available data from the archives of the Hubble Space Telescope ( HST ) and the Very Large Telescope ( VLT ) to determine the emission of this source at 1.153 \mu m ( F 110 W ) and 1.575 \mu m ( CH _ { 4 } -off ) .
J0855 - 0714 is detected at both wavelengths with signal-to-noise ratio of \approx 10 ( F 110 W ) and \approx 4 ( CH _ { 4 } -off ) at the peak of the corresponding point-spread-functions .

Results : This is the first detection of J0855 - 0714 in the H -band wavelengths .
We measure the following magnitudes : 26.31 \pm 0.10 and 23.22 \pm 0.35 mag in F 110 W and CH _ { 4 } -off ( Vega system ) .
J0855 - 0714 remains unresolved in the HST images that have a spatial resolution of 0.22″ .
Companions at separations of 0.5 AU ( similar mass and brightness ) and at \sim 1 AU ( \approx 1 mag fainter in the F 110 W filter ) are discarded .
By combining the new data with published photometry , including non-detections , we build the spectral energy distribution of J0855 - 0714 from 0.89 through 22.09 \mu m , and contrast it against state-of-the-art solar-metallicity models of planetary atmospheres .
We determine that the best spectral fit yields a temperature of 225–250 K , a bolometric luminosity of log L / L _ { \odot } = - 8.57 , and a high surface gravity of log g = 5.0 ( cm s ^ { -2 } ) , which suggests an old age although such a high gravity is not fully compatible with evolutionary models .
After comparison with the cooling theory for brown dwarfs and planets , we infer a mass in the interval 2–10 M _ { Jup } for ages of 1–12 Gyr and high atmospheric gravities of log g \gtrapprox 3.5 ( cm s ^ { -2 } ) .
If it has the age of the Sun , J0855 - 0714 would be a \approx 5-M _ { Jup } free-floating planetary-mass object .

Conclusions : J0855 - 0714 may represent the old image of the free-floating planetary-mass objects of similar mass discovered in star-forming regions and young stellar clusters .
From the extrapolation of the substellar mass functions of young clusters to the field , as many J0855 - 0714-like objects as M5–L2 stars may be expected to populate the solar neighborhood .