Sub-brown dwarf

Sub-brown dwarf is a planetary-mass object whose mass is smaller than the low-mass cut-off for brown dwarfs (around 13 times the mass of Jupiter). Unlike proper brown dwarfs, they are not massive enough to fuse deuterium. Sub-brown dwarfs are formed in the manner of stars, through the collapse of a gas cloud, and not through accretion or core collapse from a circumstellar disc. The distinction between a sub-brown dwarf and a planet is unclear; astronomers are divided into two camps as whether to consider the formation process of a planet as part of its division in classification. [ [http://www.space.com/scienceastronomy/solarsystem/planet_confusion_001101-1.html What is a Planet? Debate Forces New Definition] , by Robert Roy Britt, 02 November 2000]

An alternate definition involves the same mass range (less than a brown dwarf, but in the planetary range), but is free of gravitational attachment with any star. These are generally referred to as free-floating planets. This usage is in the IAU Extrasolar Planets provisional definition of a planet. [ [http://www.dtm.ciw.edu/boss/definition.html Working Group on Extrasolar Planets - Defintion of a "Planet"] POSITION STATEMENT ON THE DEFINITION OF A "PLANET" (IAU)]

List of suspected sub-brown dwarfs

* 2M1207b
* SCR 1845-6357 B
* Cha 110913-773444
* OTS 44

See also

* Planetar (astronomy)
* Interstellar planetary mass object
* Giant planet
* Red dwarf

References