Brown Dwarf

Brown dwarfs are substellar objects too low in mass to sustain hydrogen-1 fusion reactions in their cores, unlike main-sequence stars, which can. They occupy the mass range between the heaviest gas giants and the lightest stars, with an upper limit around 75[1]  to 80 Jupiter masses(MJ ). Brown dwarfs heavier than about 13 MJ  are thought to fuse deuterium and those above ~65 MJ , fuse lithium as well.[2]

The difference between a very-low-mass brown dwarf and a giant planet (~13 Jupiter masses) has been recently debated.[3]  One school of thought is based on formation; another, interior physics.[3]

Dwarfs are categorized by spectral classification, with the major types being M, L, T, and Y.[3]  Despite their name, brown dwarfs are different colours.[3]  Many brown dwarfs would likely appear magenta to the human eye according to A. J. Burgasser,[3]  whereas another source has noted orange/red.[4]  The term brown dwarf was not chosen to indicate their colour.[3]

Another debate is whether brown dwarfs should have experienced fusion at some point in their history. Some planets are known to orbit brown dwarfs: 2M1207b, MOA-2007-BLG-192Lb, and 2MASS J044144b. Brown dwarfs may have fully convective surfaces and interiors, with no chemical differentiation by depth.<sup class="reference" id="cite_ref-5" style="line-height:1em;unicode-bidi:-webkit-isolate;">[5]

<p style="margin-top:0.4em;margin-bottom:0.5em;line-height:19.200000762939453px;color:rgb(0,0,0);font-family:sans-serif;font-size:12.727272033691406px;">At a distance of about 6.5 light years, the nearest known brown dwarf is Luhman 16Luhman 16, a binary system of brown dwarfs discovered in 2013.