Editing Brown dwarf (section)

=== Teide&nbsp;1 and class M ===
The first confirmed class "M" brown dwarf was discovered by Spanish astrophysicists [[Rafael Rebolo]] (head of the team), María Rosa Zapatero-Osorio, and Eduardo L. Martín in 1994.<ref>{{cite web |url=http://www.iac.es/ |title=Instituto de Astrofísica de Canarias, IAC |publisher=Iac.es |access-date=2013-03-16 }}</ref> This object, found in the [[Pleiades]] open cluster, received the name [[Teide 1]]. The discovery article was submitted to ''Nature'' in May 1995, and published on 14&nbsp;September 1995.<ref name="RafaelRebolo2014">{{cite book |last=Rebolo |first=Rafael |author-link=Rafael Rebolo |title=50 Years of Brown Dwarfs – From Prediction to Discovery to Forefront of Research |volume=401 |pages=25–50 |publication-date=2014 |year=2014 |editor-last=Joergens |editor-first=Viki |series=Astrophysics and Space Science Library |chapter=Teide 1 and the Discovery of Brown Dwarfs |chapter-url=https://www.springer.com/astronomy/book/978-3-319-01161-5 |publisher=Springer |doi=10.1007/978-3-319-01162-2_4 |bibcode=2014ASSL..401...25R |isbn=978-3-319-01162-2 }}</ref><ref>{{cite journal |title=Discovery of a brown dwarf in the Pleiades star cluster |last1=Rebolo |first1=Rafael |author-link1=Rafael Rebolo |last2=Zapatero-Osorio |first2=María Rosa |last3=Martín |first3=Eduardo L. |journal=Nature |volume=377 |issue=6545 |date=September 1995 |pages=129–131 |bibcode=1995Natur.377..129R |doi=10.1038/377129a0 |s2cid=28029538 }}</ref> ''Nature'' highlighted "Brown dwarfs discovered, official" on the front page of that issue.

[[Teide 1]] was discovered in images collected by the [[Instituto de Astrofísica de Canarias|IAC]] team on 6&nbsp;January 1994 using the 80&nbsp;cm telescope (IAC&nbsp;80) at [[Teide Observatory]], and its spectrum was first recorded in December 1994 using the 4.2&nbsp;m William Herschel Telescope at [[Roque de los Muchachos Observatory]] (La Palma). The distance, chemical composition, and age of Teide&nbsp;1 could be established because of its membership in the young Pleiades star cluster. Using the most advanced stellar and substellar evolution models at that moment, the team estimated for Teide&nbsp;1 a mass of {{Jupiter mass|55 ± 15}},<ref>{{cite journal |last1=Leech |first1=Kieron |last2=Altieri |first2=Bruno |last3=Metcalfe |first3=Liam |last4=Martin |first4=Eduardo L. |last5=Rebolo |first5=Rafael |author-link5=Rafael Rebolo |last6=Zapatero-Osorio |first6=María Rosa |last7=Laureijs |first7=René J. |last8=Prusti |first8=Timo |last9=Salama |first9=Alberto |last10=Siebenmorgen |first10=Ralf |last11=Claes |first11=Peter |last12=Trams |first12=Norman |date=2000 |title=Mid-IR Observations of the Pleiades Brown Dwarfs Teide 1 & Calar 3 |journal=ASP Conference Series |volume=212 |pages=82–87 |bibcode=2000ASPC..212...82L }}</ref> which is below the stellar-mass limit. The object became a reference in subsequent young brown dwarf related works.

In theory, a brown dwarf below {{Jupiter mass|65|link=y}} is unable to burn lithium by thermonuclear fusion at any time during its evolution. This fact is one of the [[lithium]] test principles used to judge the substellar nature of low-luminosity and low-surface-temperature astronomical bodies.

High-quality spectral data acquired by the [[W. M. Keck Observatory|Keck&nbsp;1 telescope]] in November 1995 showed that Teide&nbsp;1 still had the initial lithium abundance of the original molecular cloud from which Pleiades stars formed, proving the lack of thermonuclear fusion in its core. These observations fully confirmed that Teide&nbsp;1 is a brown dwarf, as well as the efficiency of the spectroscopic [[Lithium burning|lithium test]].<ref>{{cite journal |author1=R. Rebolo |author2=E. L. Martín |author3=G. Basri |author4=G. W. Marcy |author5=M. R. Zapatero-Osorio |date=1996 |title=Brown Dwarfs in the Pleiades Cluster Confirmed by the Lithium Test |journal=The Astrophysical Journal |volume=469 |pages=53–56 |arxiv=astro-ph/9607002 |bibcode=1996ApJ...469L..53R |doi=10.1086/310263 |s2cid=119485127}}</ref>

For some time, Teide&nbsp;1 was the smallest known object outside the Solar System that had been identified by direct observation. Since then, over 1,800&nbsp;brown dwarfs have been identified,<ref name="DwarfArchives"/> even some very close to Earth, like [[Epsilon Indi]]&nbsp;Ba and Bb, a pair of brown dwarfs gravitationally bound to a Sun-like star 12&nbsp;light-years from the Sun,<ref>{{cite journal |title=Epsilon Indi Ba/Bb: the nearest binary brown dwarf |first1=Mark J. |last1=McCaughrean |first2=Laird M. |last2=Close |first3=Ralf-Dieter |last3=Scholz |first4=Rainer |last4=Lenzen |first5=Beth A. |last5=Biller |first6=Wolfgang |last6=Brandner |first7=Markus |last7=Hartung |first8=Nicolas |last8=Lodieu |journal=Astronomy & Astrophysics |volume=413 |issue=3 |date=January 2004 |pages=1029–1036 |doi=10.1051/0004-6361:20034292 |arxiv=astro-ph/0309256|s2cid=15407249 }}</ref> and Luhman 16, a binary system of brown dwarfs at 6.5&nbsp;light-years from the Sun.