I wonder if all these strange objects are in SE. Some are rogue planets, some are brown dwarfs some are in between. The first one, like the WISE object you mentioned, has water in its atmosphere (and also methane.)
https://en.wikipedia.org/wiki/CFBDSIR_2149-0403
Atmosphere[edit]
File:Artist's impression of the free-floating planet CFBDSIR J214947.2-040308.9.ogv
This video shows an artist's impression of the free-floating planet CFBDSIR J214947.2-040308.9.
Spectroscopy observations have found absorption by gaseous methane and water.[1]
https://en.wikipedia.org/wiki/GU_Piscium_b
https://en.wikipedia.org/wiki/PSO_J318.5-22
https://en.wikipedia.org/wiki/GU_Piscium_b
https://en.wikipedia.org/wiki/WD_0806-661
Component B was discovered in 2011 with Spitzer Space Telescope. Its discovery paper is Luhman et al., 2011. At the time of its discovery, WD 0806-661 B was the coldest "star" that has ever been found, with a temperature of only 27–80 °C, which is similar to some hot areas of Earth.[9]
https://en.wikipedia.org/wiki/HD_106906_b
https://en.wikipedia.org/wiki/DT_Virginis
https://en.wikipedia.org/wiki/QS_Virginis
https://en.wikipedia.org/wiki/NN_Serpentis
https://en.wikipedia.org/wiki/Kepler-16
https://en.wikipedia.org/wiki/GU_Psc_b
https://en.wikipedia.org/wiki/CM_Draconis
https://en.wikipedia.org/wiki/List_of_e ... ar_planets
https://en.wikipedia.org/wiki/List_of_e ... cteristics
https://en.wikipedia.org/wiki/List_of_e ... t_extremes
https://en.wikipedia.org/wiki/Luhman_16
https://en.wikipedia.org/wiki/List_of_n ... own_dwarfs
https://en.wikipedia.org/wiki/WISE_0855%E2%88%920714
Spectrometry[edit]
Its luminosity in different bands of the thermal infrared in combination with its absolute magnitude—because of its known distance—was used to place it in context of different models; the best characterization of its brightness was in the W2 band of 4.6 µm at an apparent magnitude of 13.89±0.05, though it was brighter into the deeper infrared.[3] Infrared images taken with the Magellan Baade telescope suggest evidence of water clouds.[4]
Model-derived understanding[edit]
Based on models of brown dwarfs WISE 0855−0714's is estimated to have a mass of 3 to 10 MJup.[1] This mass is in the range of a sub-brown dwarf or other planetary-mass object.
As of 2003, the International Astronomical Union considers an object with a mass above 13 MJup to be capable of fusing deuterium and to be designated a brown dwarf. A lighter object and one orbiting another object is considered a planet.[5] So far this WISE object is alone, though it could be a rogue planet, something first identified in 2004 in the case of Cha 110913-773444.[6]
Combining its luminosity, distance, and mass it is estimated to be the coldest known brown dwarf, with a modeled effective temperature of 225 to 260 K (−48 to −13 °C; −55 to 8 °F), depending on the model.[1]