Editing Brown dwarf (section)

=== Spectral and atmospheric properties of brown dwarfs ===
[[File:Anatomy of Brown Dwarf's Atmosphere.jpg|thumb|Artist's illustration of a brown dwarf's interior structure. Cloud layers at certain depths are offset as a result of layer shifting.]]
The majority of flux emitted by L and T dwarfs is in the 1- to 2.5-micrometre near-infrared range. Low and decreasing temperatures through the late-M, -L, and -T dwarf sequence result in a rich near-infrared [[spectrum]] containing a wide variety of features, from relatively narrow lines of neutral atomic species to broad molecular bands, all of which have different dependencies on temperature, gravity, and [[metallicity]]. Furthermore, these low temperature conditions favor condensation out of the gas state and the formation of grains.

[[File:PIA23684-BrownDwarfStar-Wind-SpitzerST-ArtistConcept-20200409.jpg|thumb|left|150px|Wind measured (Spitzer ST; artist's concept; 9 April 2020)<ref name="EA-20200409">{{cite news |author=[[National Radio Astronomy Observatory]] |title=Astronomers measure wind speed on a brown dwarf – Atmosphere, interior rotating at different speeds |url=https://www.eurekalert.org/pub_releases/2020-04/nrao-amw040620.php |date=9 April 2020 |work=[[EurekAlert!]] |access-date=10 April 2020 }}</ref>
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Typical atmospheres of known brown dwarfs range in temperature from 2200 down to {{Val|750|ul=K}}.<ref name=burrows/> Compared to stars, which warm themselves with steady internal fusion, brown dwarfs cool quickly over time; more massive dwarfs cool more slowly than less massive ones. There is some evidence that the cooling of brown dwarfs slows down at the transition between spectral classes L and T (about 1000 K).<ref>{{cite journal|doi=10.3847/1538-3881/ac66d2|title=Precise Dynamical Masses of ε Indi Ba and Bb: Evidence of Slowed Cooling at the L/T Transition |year=2022 |last1=Chen |first1=Minghan |last2=Li |first2=Yiting |last3=Brandt |first3=Timothy D. |last4=Dupuy |first4=Trent J. |last5=Cardoso |first5=Cátia V. |last6=McCaughrean |first6=Mark J. |journal=The Astronomical Journal |volume=163 |issue=6 |page=288 |arxiv=2205.08077 |bibcode=2022AJ....163..288C |s2cid=248834536 |doi-access=free }}</ref>

Observations of known brown dwarf candidates have revealed a pattern of brightening and dimming of infrared emissions that suggests relatively cool, opaque cloud patterns obscuring a hot interior that is stirred by extreme winds. The weather on such bodies is thought to be extremely strong, comparable to but far exceeding Jupiter's famous storms.

On January 8, 2013, astronomers using NASA's [[Hubble Space Telescope|Hubble]] and [[Spitzer Space Telescope|Spitzer]] space telescopes probed the stormy atmosphere of a brown dwarf named [[2MASS J22282889–4310262]], creating the most detailed "weather map" of a brown dwarf thus far. It shows wind-driven, planet-sized clouds. The new research is a stepping stone toward a better understanding not only brown dwarfs, but also of the atmospheres of planets beyond the Solar System.<ref>{{cite web |url=http://hubblesite.org/newscenter/archive/releases/star/brown-dwarf/2013/02/ |title=NASA Space Telescopes See Weather Patterns in Brown Dwarf |website=Hubblesite |publisher=NASA |access-date=8 January 2013 |archive-date=2 April 2014 |archive-url=https://web.archive.org/web/20140402162957/http://hubblesite.org/newscenter/archive/releases/star/brown-dwarf/2013/02/ |url-status=dead }}</ref>

In April 2020 scientists reported measuring wind speeds of {{val|+650|310|u=metres per second}} (up to 1,450 miles per hour) on the nearby brown dwarf [[2MASS J10475385+2124234]]. To calculate the measurements, scientists compared the rotational movement of atmospheric features, as ascertained by brightness changes, against the electromagnetic rotation generated by the brown dwarf's interior. The results confirmed previous predictions that brown dwarfs would have high winds. Scientists are hopeful that this comparison method can be used to explore the atmospheric dynamics of other brown dwarfs and extrasolar planets.<ref>{{cite web|url=https://www.cnn.com/2020/04/09/world/brown-dwarf-wind-speed-scn/index.html|title=Astronomers Clock High Winds on Object Outside Our Solar System|website=CNN|date=9 April 2020 |publisher=CNN|access-date=11 April 2020}}</ref>