Editing Brown dwarf (section)

==== Lithium test ====
Brown dwarfs can be divided into two groups, those with enough mass fuse lithium and those with smaller mass. This is known as the '''lithium test'''.<ref>{{Cite journal |last1=Martín |first1=E L |last2=Lodieu |first2=N |last3=del Burgo |first3=C |date=2022-02-21 |title=New constraints on the minimum mass for thermonuclear lithium burning in brown dwarfs |journal=Monthly Notices of the Royal Astronomical Society |volume=510 |issue=2 |pages=2841–2850 |doi=10.1093/mnras/stab2969 |doi-access=free |issn=0035-8711}}</ref>

Heavier stars, like the Sun, can also retain lithium in their outer layers, which never get hot enough to fuse lithium, and whose convective layer does not mix with the core where the lithium would be rapidly depleted. Those larger stars are easily distinguishable from brown dwarfs by their size and luminosity.

Conversely, brown dwarfs at the high end of their mass range can be hot enough to deplete their lithium when they are young. Dwarfs of mass greater than {{Jupiter mass|65}} can burn their lithium by the time they are half a billion years old.<ref>{{cite journal |last1=Kulkarni |first1=Shrinivas R. |author-link=Shrinivas Kulkarni |title=Brown Dwarfs: A Possible Missing Link Between Stars and Planets |journal=Science |date=30 May 1997 |volume=276 |issue=5317 |pages=1350–1354 |doi=10.1126/science.276.5317.1350 |bibcode=1997Sci...276.1350K }}</ref>