WISE 0855−0714 is a sub-brown dwarf 2.28±0.01 parsecs from Earth, therefore the fourth-closest star or (sub-) brown dwarf system to the Sun, the discovery of which was announced in April 2014 by Kevin Luhman using data from the Wide-field Infrared Survey Explorer (WISE). As of 2014, WISE 0855−0714 has the third-highest proper motion after Barnard's Star and Kapteyn's Star and the fourth-largest parallax of any known star or brown dwarf. It is also the coldest object of its type found in interstellar space, having a temperature of about 285 K.

A sub-brown dwarf or planetary-mass brown dwarf is an astronomical object that formed in the same manner as stars and brown dwarfs but that has a planetary mass, therefore by definition below the limiting mass for thermonuclear fusion of deuterium . Some researchers call them rogue planets whereas others call them planetary-mass brown dwarfs. They are sometimes categorized as Y spectral class brown dwarfs.