Editing Exoplanet (section)

=== Moons ===
{{Main|Exomoon}}There is evidence that moons around other planets, commonly referred to exomoons, may exist. None has been confirmed so far.

In 2012 a candidate exomoon was detected around WASP-12b via periodic light variations in the planet's [[light curve]].<ref>[http://www.ria.ru/science/20120206/558647431.html Российские астрономы впервые открыли луну возле экзопланеты] (in Russian) - "Studying of a curve of change of shine of WASP-12b has brought to the Russian astronomers unusual result: regular splashes were found out.<...> Though stains on a star surface also can cause similar changes of shine, observable splashes are very similar on duration, a profile and amplitude that testifies for benefit of exomoon existence."</ref> Subsequent observations found this object might actually be a [[trojan planet]].<ref>{{citation |last1=Kislyakova |first1=K. G. |title=On the ultraviolet anomalies of the WASP-12 and HD 189733 systems: Trojan satellites as a plasma source |journal=Monthly Notices of the Royal Astronomical Society |volume=461 |issue=1 |pages=988–999 |year=2016 |arxiv=1605.02507 |bibcode=2016MNRAS.461..988K |doi=10.1093/mnras/stw1110 |s2cid=119205132 |last2=Pilat-Lohinger |first2=E. |last3=Funk |first3=B. |last4=Lammer |first4=H. |last5=Fossati |first5=L. |last6=Eggl |first6=S. |last7=Schwarz |first7=R. |last8=Boudjada |first8=M. Y. |last9=Erkaev |first9=N. V. |doi-access=free}}</ref>

In December 2013, a candidate exomoon was detected in the microlensing event [[MOA-2011-BLG-262L|MOA-2011-BLG-262]], it was believed to be either a {{Earth mass|0.5|link=y}} exomoon around a Jupiter-sized free-floating planet or a Neptune-mass planet around a red dwarf,<ref>{{Cite journal | doi = 10.1088/0004-637X/785/2/155|arxiv=1312.3951| title = MOA-2011-BLG-262Lb: A sub-Earth-mass moon orbiting a gas giant or a high-velocity planetary system in the galactic bulge| journal = The Astrophysical Journal| volume = 785| issue = 2| page = 155| year = 2014| last1 = Bennett | first1 = D. P.| last2 = Batista | first2 = V.| last3 = Bond | first3 = I. A.| last4 = Bennett | first4 = C. S.| last5 = Suzuki | first5 = D.| last6 = Beaulieu | first6 = J. -P. | last7 = Udalski | first7 = A.| last8 = Donatowicz | first8 = J.| last9 = Bozza | first9 = V.| last10 = Abe | first10 = F.| last11 = Botzler | first11 = C. S.| last12 = Freeman | first12 = M.| last13 = Fukunaga | first13 = D.| last14 = Fukui | first14 = A.| last15 = Itow | first15 = Y.| last16 = Koshimoto | first16 = N.| last17 = Ling | first17 = C. H.| last18 = Masuda | first18 = K.| last19 = Matsubara | first19 = Y.| last20 = Muraki | first20 = Y.| last21 = Namba | first21 = S.| last22 = Ohnishi | first22 = K.| last23 = Rattenbury | first23 = N. J.| last24 = Saito | first24 = T. | last25 = Sullivan | first25 = D. J.| last26 = Sumi | first26 = T.| last27 = Sweatman | first27 = W. L.| last28 = Tristram | first28 = P. J.| last29 = Tsurumi | first29 = N.| last30 = Wada | first30 = K.| display-authors = etal|bibcode=2014ApJ...785..155B|s2cid=118327512}}</ref> but follow-up observations confirmed the latter scenario.<ref name="Terry2024">{{Cite journal |arxiv=2410.09147 |first1=Sean K. |last1=Terry |first2=Jean-Philippe |last2=Beaulieu |title=A Candidate High-velocity Exoplanet System in the Galactic Bulge |date=2025 |last3=Bennett |first3=David P. |last4=Bhattacharya |first4=Aparna |last5=Hulberg |first5=Jon |last6=Huston |first6=Macy J. |last7=Koshimoto |first7=Naoki |last8=Blackman |first8=Joshua W. |last9=Bond |first9=Ian A.|journal=The Astronomical Journal |volume=169 |issue=3 |page=131 |doi=10.3847/1538-3881/ad9b0f |doi-access=free |bibcode=2025AJ....169..131T }}</ref> 

On 3 October 2018, evidence suggesting a large exomoon orbiting [[Kepler-1625b]] was reported,<ref>{{Cite journal|last1=Teachey|first1=Alex|last2=Kipping|first2=David M.|date=1 October 2018|title=Evidence for a large exomoon orbiting Kepler-1625b|journal=Science Advances|language=en|volume=4|issue=10|pages=eaav1784|doi=10.1126/sciadv.aav1784|pmid=30306135|pmc=6170104|issn=2375-2548|bibcode=2018SciA....4.1784T|arxiv=1810.02362}}</ref> and in 2021 evidence of an exomoon around Kepler-1708b was also reported.<ref>{{Cite news |title=Scientists think they've found a big, weird moon in a far-off star system |url=https://www.npr.org/2022/01/13/1072570125/kepler-large-exomoon |access-date=2022-03-28 |work=NPR.org |language=en}}</ref> Their existence, however, remain doubtful,<ref>{{cite journal |last1=Heller |first1=René |last2=Hippke |first2=Michael |date=2024 |title=Large exomoons unlikely around Kepler-1625 b and Kepler-1708 B |url=https://ui.adsabs.harvard.edu/abs/2024NatAs...8..193H/abstract |journal=Nature Astronomy |volume=8 |issue=2 |page=193 |arxiv=2312.03786 |bibcode=2024NatAs...8..193H |doi=10.1038/s41550-023-02148-w}}</ref> but follow-up observations may confirm these exomoons.<ref>{{Cite arXiv |eprint=2401.10333 |first1=David |last1=Kipping |first2=Alex |last2=Teachey |title=A Reply to: Large Exomoons unlikely around Kepler-1625 b and Kepler-1708 b |date=2024-01-18 |last3=Yahalomi |first3=Daniel A. |last4=Cassese |first4=Ben |last5=Quarles |first5=Billy |last6=Bryson |first6=Steve |last7=Hansen |first7=Brad |last8=Szulágyi |first8=Judit |last9=Burke |first9=Chri|class=astro-ph.EP }}</ref>

The detection of [[sodium]] in hot Jupiters such as [[WASP-76b]], [[HD 189733 b]] or [[WASP-49b]] is likely due to a [[Io (moon)|Io]]-like exomoon around these planets.<ref>{{Cite journal |last1=Oza |first1=Apurva V. |last2=Johnson |first2=Robert E. |last3=Lellouch |first3=Emmanuel |last4=Schmidt |first4=Carl |last5=Schneider |first5=Nick |last6=Huang |first6=Chenliang |last7=Gamborino |first7=Diana |last8=Gebek |first8=Andrea |last9=Wyttenbach |first9=Aurelien |last10=Demory |first10=Brice-Olivier |last11=Mordasini |first11=Christoph |last12=Saxena |first12=Prabal |last13=Dubois |first13=David |last14=Moullet |first14=Arielle |last15=Thomas |first15=Nicolas |date=2019-08-28 |title=Sodium and Potassium Signatures of Volcanic Satellites Orbiting Close-in Gas Giant Exoplanets |journal=[[The Astrophysical Journal]] |volume=885 |issue=2 |pages=168 |arxiv=1908.10732 |bibcode=2019ApJ...885..168O |doi=10.3847/1538-4357/ab40cc |s2cid=201651224 |doi-access=free}}</ref><ref>{{cite journal |last1=Gebek |first1=Andrea |last2=Oza |first2=Apurva |date=29 July 2020 |title=Alkaline exospheres of exoplanet systems: evaporative transmission spectra |url=https://academic.oup.com/mnras/article-abstract/497/4/5271/5877918?redirectedFrom=fulltext |journal=Monthly Notices of the Royal Astronomical Society |volume=497 |issue=4 |pages=5271–5291 |arxiv=2005.02536 |bibcode=2020MNRAS.497.5271G |doi=10.1093/mnras/staa2193 |s2cid=218516741 |access-date=8 December 2020 |doi-access=free}}</ref>