Topic summary
Sub-brown dwarf
A sub-brown dwarf or planetary-mass brown dwarf is an astronomical object that formed in the same manner as stars and brown dwarfs (i.e. through the collapse of a gas cloud) but that has a planetary mass, therefore by definition below the limiting mass for thermonuclear fusion of deuterium (about 13MJ). Some researchers include them in the category of rogue planets whereas others call them planetary-mass brown dwarfs.