Changes

===Spectral class L===

===Spectral class L===

L dwarfs are defined in the red opitcal region, much like M class stars, but have spectra defined by strong metal hydride bands (FeH, CrH, MgH, CaH) and alkali lines (Na I, K I, Cs I, Rb I).<ref name="bdref"/>  The surface temperature of of L class dwarfs typical average around 1,500K to 2,200K.  [[Teide 1]] is an example of a L dwarf.

L dwarfs are defined in the red opitcal region, much like M class stars, but have spectra defined by strong metal hydride bands (FeH, CrH, MgH, CaH) and alkali lines (Na I, K I, Cs I, Rb I).<ref name="bdref"/>  The surface temperature of L class dwarfs typical average around 1,500K to 2,200K.  [[Teide 1]] is an example of a L dwarf.

===Spectral class T===

===Spectral class T===

Because of the very limited amount of light brown dwarfs give, methods other then observations in the visual spectrum are used to discover them.  One method of detection is through the large amount of infrared radiation such objects emit, allowing observations using infrared equipment, brown dwarfs are also distinguishable from planets through their emission of [[x-ray]]s.  They are also detected via the wobble that a brown dwarf would cause in the motion of a parent or companion star.  Thus [[radial velocity]] is used to find a large amount of brown dwarfs.  A telescope equipped with a [[coronagraph]] may also be used to detect brown dwarfs.

Because of the very limited amount of light brown dwarfs give, methods other then observations in the visual spectrum are used to discover them.  One method of detection is through the large amount of infrared radiation such objects emit, allowing observations using infrared equipment, brown dwarfs are also distinguishable from planets through their emission of [[x-ray]]s.  They are also detected via the wobble that a brown dwarf would cause in the motion of a parent or companion star.  Thus [[radial velocity]] is used to find a large amount of brown dwarfs.  A telescope equipped with a [[coronagraph]] may also be used to detect brown dwarfs.

The most significant indicator used to differentiate between brown dwarfs, and very low mass, cool [[red dwarf]]s is the presence of [[lithium]], often referred to as the ''Lithium test''.  This is due to red dwarf stars having sufficient temperature to quickly deplete any lithium available, which occurs when lithium-7 and a proton collide to produce two helium-4 atoms. As red dwarfs transport energy to the surface entirely through convection, all the lithium in the star is converted over time.  Normally, brown dwarfs lack the mass and temperature to exhaust the available lithium, however higher mass brown dwarfs of .0065 solar masses or greater, have sufficient temperature to also expend their lithium (which is slightly lower then the temperature required to fuse hydrogen), abet over a longer period of time.<ref name="bdref"/>

The most significant indicator used to differentiate between brown dwarfs, and very low mass, cool [[red dwarf]]s is the presence of [[lithium]], often referred to as the ''Lithium test''.  This is due to red dwarf stars having sufficient temperature to quickly deplete any lithium available, which occurs when lithium-7 and a proton collide to produce two helium-4 atoms. As red dwarfs transport energy to the surface entirely through convection, all the lithium in the star is converted over time.  Normally, brown dwarfs lack the mass and temperature to exhaust the available lithium, however higher mass brown dwarfs of .0065 solar masses or greater, have sufficient temperature to also expend their lithium (which is slightly lower than the temperature required to fuse hydrogen), abet over a longer period of time.<ref name="bdref"/>

For the coolest and least massive brown dwarfs, the main method to distinguish them from large gas giants is density. Even though all brown dwarfs are around the same radius, which is close to the radius of the largest gas giants, they are many times more massive, and thus more dense.  Typically the higher volume of a brown dwarf is controlled through [[electron degeneracy]], although the least massive brown dwarfs' volume is controlled through [[Coulomb pressure]].<ref>http://arxiv.org/abs/astro-ph/0608417</ref>   

For the coolest and least massive brown dwarfs, the main method to distinguish them from large gas giants is density. Even though all brown dwarfs are around the same radius, which is close to the radius of the largest gas giants, they are many times more massive, and thus more dense.  Typically the higher volume of a brown dwarf is controlled through [[electron degeneracy]], although the least massive brown dwarfs' volume is controlled through [[Coulomb pressure]].<ref>http://arxiv.org/abs/astro-ph/0608417</ref>