Editing Exoplanet (section)

=== Atmospheres ===
{{main|Exoplanet atmosphere}}
[[File:Cloudy versus clear atmospheres on two exoplanets.jpg|thumb|upright=1.6|Clear versus cloudy atmospheres on two exoplanets.<ref>{{cite web|title=Cloudy versus clear atmospheres on two exoplanets|url=https://www.spacetelescope.org/images/opo1722a/|website=www.spacetelescope.org|access-date=6 June 2017}}</ref>]]

Atmospheres have been detected around several exoplanets. The first to be observed was [[HD 209458 b]] in 2001.<ref>{{cite journal|last=Charbonneau|first=David|display-authors=etal|year=2002|title=Detection of an Extrasolar Planet Atmosphere|journal=The Astrophysical Journal|volume=568|issue=1|pages=377–384|arxiv=astro-ph/0111544|bibcode=2002ApJ...568..377C|doi=10.1086/338770|s2cid=14487268}}</ref>

[[File:PIA18410-TitanSunsetStudies-CassiniSpacecraft-20140527.jpg|thumb|upright=1.4|alt=Artist's concept of the ''Cassini'' spacecraft in front of a sunset on Saturn's moon Titan|Sunset studies on [[Titan (moon)|Titan]] by [[Cassini (spacecraft)|''Cassini'']] help understand exoplanet [[atmosphere]]s (artist's concept).]]
As of February 2014, more than fifty [[Transit method|transiting]] and five [[Direct imaging|directly imaged]] exoplanet atmospheres have been observed,<ref>{{cite book |last1=Madhusudhan|first1=Nikku|pages=739|last2=Knutson|first2=Heather|last3=Fortney|first3=Jonathan|last4=Barman|first4=Travis|title=Protostars and Planets VI| year=2014|  doi=10.2458/azu_uapress_9780816531240-ch032|chapter=Exoplanetary Atmospheres|isbn=978-0-8165-3124-0|arxiv = 1402.1169 |bibcode = 2014prpl.conf..739M |s2cid=118337613}}</ref> resulting in detection of molecular spectral features; observation of day–night temperature gradients; and constraints on vertical atmospheric structure.<ref name="SeagerDeming2010">{{cite journal |arxiv=1005.4037 |last1=Seager |first1=S. |last2=Deming |first2=D. |title=Exoplanet Atmospheres |date=2010|doi = 10.1146/annurev-astro-081309-130837 |bibcode = 2010ARA&A..48..631S |volume=48 |journal=Annual Review of Astronomy and Astrophysics |pages=631–672|s2cid=119269678 }}</ref> Also, an atmosphere has been detected on the non-transiting hot Jupiter [[Tau Boötis b]].<ref name="Rodler2012">{{cite journal | title=Weighing the Non-transiting Hot Jupiter τ Boo b | last1=Rodler | first1=F. | last2=Lopez-Morales | first2=M. | last3=Ribas | first3=I. | journal=The Astrophysical Journal Letters | volume=753 | issue=1 | pages=L25 | id=L25| date=July 2012 | arxiv=1206.6197 | bibcode=2012ApJ...753L..25R | doi=10.1088/2041-8205/753/1/L25 | s2cid=119177983 }}</ref><ref>{{Cite journal | doi = 10.1038/nature11161| pmid = 22739313| title = The signature of orbital motion from the dayside of the planet τ Boötis b| journal = Nature| volume = 486| issue = 7404| pages = 502–504| year = 2012| last1 = Brogi | first1 = M. | last2 = Snellen | first2 = I. A. G. | last3 = De Kok | first3 = R. J. | last4 = Albrecht | first4 = S. | last5 = Birkby | first5 = J. | last6 = De Mooij | first6 = E. J. W. |arxiv = 1206.6109 |bibcode = 2012Natur.486..502B | s2cid = 4368217}}</ref>

In May 2017, glints of light from [[Earth]], seen as twinkling from an orbiting satellite a million miles away, were found to be [[Reflection (physics)|reflected light]] from [[ice crystals]] in the [[Atmosphere of Earth|atmosphere]].<ref name="NYT-20170519">{{cite news |last=St. Fleur |first=Nicholas |title=Spotting Mysterious Twinkles on Earth From a Million Miles Away |url=https://www.nytimes.com/2017/05/19/science/dscovr-satellite-ice-glints-earth-atmosphere.html |archive-url=https://ghostarchive.org/archive/20220101/https://www.nytimes.com/2017/05/19/science/dscovr-satellite-ice-glints-earth-atmosphere.html |archive-date=2022-01-01 |url-access=limited |date=19 May 2017 |work=The New York Times |access-date=20 May 2017}}{{cbignore}}</ref><ref name="GRL-201760515">{{cite journal |last1=Marshak |first1=Alexander |last2=Várnai |first2=Tamás |last3=Kostinski |first3=Alexander |title=Terrestrial glint seen from deep space: oriented ice crystals detected from the Lagrangian point|date=15 May 2017 |journal=[[Geophysical Research Letters]] |doi=10.1002/2017GL073248 |volume=44 |issue=10 |pages=5197–5202|bibcode = 2017GeoRL..44.5197M |s2cid=109930589 |url=https://zenodo.org/record/1229066|hdl=11603/13118 |hdl-access=free }}</ref> The technology used to determine this may be useful in studying the atmospheres of distant worlds, including those of exoplanets.

==== Comet-like tails ====
[[Kepler-1520b]] is a small rocky planet, very close to its star, that is evaporating and leaving a trailing tail of cloud and dust like a [[comet]].<ref>{{Cite web|last=University|first=Leiden|title=Evaporating exoplanet stirs up dust|url=https://phys.org/news/2012-08-evaporating-exoplanet.html|access-date=2022-01-17|website=phys.org|language=en}}</ref> The dust could be ash erupting from volcanos and escaping due to the small planet's low surface-gravity, or it could be from metals that are vaporized by the high temperatures of being so close to the star with the metal vapor then condensing into dust.<ref>{{Cite web|date=2012-05-18|title=New-found exoplanet is evaporating away|url=https://tgdaily.com/science/space/63469-new-found-exoplanet-is-evaporating-away/|access-date=2022-01-17|website=TGDaily|language=en-US}}</ref>

In June 2015, scientists reported that the atmosphere of [[GJ 436 b]] was evaporating, resulting in a giant cloud around the planet and, due to radiation from the host star, a long trailing tail {{convert|9|e6mi|e6km|order=flip|abbr=unit}} long.<ref name="NYT-20150625">{{cite news |last=Bhanoo |first=Sindya N. |title=A Planet with a Tail Nine Million Miles Long |url=https://www.nytimes.com/interactive/projects/cp/summer-of-science-2015/latest/exoplanet-tail |date=25 June 2015 |work=[[The New York Times]] |access-date=25 June 2015}}</ref>