"Hundreds of potential Brown Dwarfs" from WISE

http://www.telegraph.co.uk/science/space/7894247/Nasa-elated-after-new-telescope-uncovers-previously-invisible-space-objects.html

No details on individual objects yet.

Thread bump for a significant update about mass and distance of ultracool (sub)dwarf WISE J181005.5-101002.3 in Serpens (Cauda), which turns out to be located at 8.9^+0.7_-0.6 pc, metal-poor ([Fe/H] = -1.5) and yield a mass about 17 _-12⁺⁵⁶ M_Jup and radius of ca. 0.65 R_Jup, compatible values with a rather massive rogue planet. Even the spectral type seems to be unique and hard to characterize.

Physical properties and trigonometric distance of the peculiar dwarf WISE J181005.5

Quote :

Our goal is to characterise the physical properties of the metal-poor brown dwarf population. In particular, we focus on the recently discovered peculiar dwarf WISE J1810055−1010023. We collected optical iz and near-infrared J-band imaging on multiple occasions over 1.5 years to derive accurate trigonometric parallax and proper motion of the metal-depleted ultra-cool dwarf candidate WISE1810. We also acquired low-resolution optical spectroscopy (0.6-1.0 μm) and new infrared (0.9-1.3 μm) spectra of WISE1810 that were combined with our photometry, other existing data from the literature and our trigonometric distance to determine the object's luminosity from the integration of the observed spectral energy distribution covering from 0.6 through 16μm. We compared the full optical and infrared spectrum with state-of-the-art atmosphere models to further constrain its effective temperature, surface gravity and metallicity. WISE1810 is detected in the iz bands with AB magnitudes of i=23.871±0.104 and z=20.147±0.083 mag in the PanSTARRS system. It does not show any obvious photometric variability beyond 0.1-0.2 mag in any of the z- and J-band filters. The very red z−J≈2.9 mag colour is compatible with an ultra-cool dwarf nature. Fitting for parallax and proper motion, we measure a trigonometric parallax of 112.5^+8.1_-8.0 mas for WISE1810, placing the object at only 8.9^+0.7_-0.6 pc, about three times closer than previously thought. We employed Monte Carlo methods to estimate the error on the parallax and proper motion. The object's luminosity was determined at logL/L⊙=-5.78±0.11 dex. From the comparison to atmospheric models, we infer a likely metallicity of [Fe/H] ≈-1.5 and an effective temperature cooler than 1000K.

Being listed also in WISE catalog, I think it's the right thread. Atmospheric characterization of isolated nearby (5.21 pc) brown dwarf 2MASS 08173001-6155158:

A 1.46-2.48 μm Spectroscopic Atlas of a T6 Dwarf (1060 K) Atmosphere with IGRINS: First Detections of H₂S and H₂, and Verification of H₂O, CH₄, and NH₃ Line Lists

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We present Gemini South/IGRINS observations of the 1060 K T6 dwarf 2MASS J08173001-6155158 with unprecedented resolution (R≡λ/Δλ=45000) and signal-to-noise ratio (SNR > 200) for a late-type T dwarf. We use this benchmark observation to test the reliability of molecular line lists used up-to-date atmospheric models. We determine which spectroscopic regions should be used to estimate the parameters of cold brown dwarfs and, by extension, exoplanets. We present a detailed spectroscopic atlas with molecular identifications across the H and K bands of the near-infrared. We find that water (H₂O) line lists are overall reliable. We find the most discrepancies amongst older methane (CH₄) line lists, and that the most up-to-date CH₄ line lists correct many of these issues. We identify individual ammonia (NH₃) lines, a hydrogen sulfide (H₂S) feature at 1.5900 μm, and a molecular hydrogen (H₂) feature at 2.1218 μm. These are the first unambiguous detections of H₂S and H₂ absorption features in an extra-solar atmosphere. With the H₂ detection, we place an upper limit on the atmospheric dust concentration of this T6 dwarf: at least 500 times less than the interstellar value, implying that the atmosphere is effectively dust-free. We additionally identify several features that do not appear in the model spectra. Our assessment of the line lists is valuable for atmospheric model applications to high-dispersion, low-SNR, high-background spectra, such as an exoplanet around a star. We demonstrate a significant enhancement in the detection of the CH₄ absorption signal in this T6 dwarf with the most up-to-date line lists.

Wikipedia entry for 2MASS 08173001-6155158 (as DENIS J081730.0-615520), the mass is about 15 Jupiter masses, more compatible with a massive SuperJovian rogue planet with hydrogen and methane-rich atmosphere than a brown dwarf. Key reference Artigau et al. (2010).