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A '''Brown Dwarf''' is a sub-stellar object that has an intermediate mass between a [[star]] and a large gas giant [[planet]].  Sometimes described as "failed stars", they lack the necessary mass to start or maintain hydrogen burning nuclear [[fusion]] reactions in their cores.  These objects are not actually "brown" in color, but a very dull red, as most of their radiation is emitted in the [[infrared]].

A '''Brown Dwarf''' is a sub-stellar object that has an intermediate mass between a [[star]] and a large gas giant [[planet]].  Sometimes described as "failed stars", they lack the necessary mass to start or maintain hydrogen burning nuclear [[fusion]] reactions in their cores.  These objects are not actually "brown" in color, but a very dull red, as most of their radiation is emitted in the [[infrared]].

Brown dwarfs are primarily identified by their mass and origin, with mass being the most common method of classification.  According to current models of star formation, a mass of at least .0075 that of our [[Sun]] (or 75 times [[Jupiter|Jupiter's]] mass) is required to initiate core [[hydrogen]] fusion, establishing this is the upper limit of the mass of a brown dwarf.  The lower limit of .0013 masses of the Sun (or 13 times the mass of Jupiter) is more of an arbitrary number as there is no clear transition between a high mass gas giant and a low mass brown dwarf.  However around .0013 solar masses is what is required to fuse [[deuterium]], and isthe  lower mass limit established by the [[International Astronomical Union]] for a sub-stellar object to be classified as a brown dwarf, any substellar object of lower mass that orbits a star or stellar remnant is considered a planet.<ref>http://www.dtm.ciw.edu/boss/definition.html</ref> Brown dwarfs are also seen as different from planets as they are believed to form the same was as stars do, through the compression of interstellar gas clouds, instead of forming in the circumstellar disk as a planet would.<ref name="bdref">http://www.daviddarling.info/encyclopedia/B/browndwarf.html</ref>  

Brown dwarfs are primarily identified by their mass and origin, with mass being the most common method of classification.  According to current models of star formation, a mass of at least .0075 that of our [[Sun]] (or 75 times [[Jupiter|Jupiter's]] mass) is required to initiate core [[hydrogen]] fusion, establishing this is the upper limit of the mass of a brown dwarf.  The lower limit of .0013 masses of the Sun (or 13 times the mass of Jupiter) is more of an arbitrary number as there is no clear transition between a high mass gas giant and a low mass brown dwarf.  However around .0013 solar masses is what is required to fuse [[deuterium]], and is the lower mass limit established by the [[International Astronomical Union]] for a sub-stellar object to be classified as a brown dwarf, any substellar object of lower mass that orbits a star or stellar remnant is considered a planet.<ref>http://www.dtm.ciw.edu/boss/definition.html</ref> Brown dwarfs are also seen as different from planets as they are believed to form the same was as stars do, through the compression of interstellar gas clouds, instead of forming in the circumstellar disk as a planet would.<ref name="bdref">http://www.daviddarling.info/encyclopedia/B/browndwarf.html</ref>  

==History==

==History==