Editing Alpha Centauri (section)

=== {{anchor|Unconfirmed planets}}Planets of Alpha Centauri B ===
{{Main|Alpha Centauri Bb}}

The first claim of a planet around Alpha Centauri B was that of [[Alpha Centauri Bb]] in 2012, which was proposed to be an Earth-mass planet in a 3.2-day orbit.<ref name="Dumusque"/> This was refuted in 2015 when the apparent planet was shown to be an artifact of the way the [[Doppler spectroscopy|radial velocity]] data was processed.<ref>{{cite news |last=Wenz |first=John |date=2015-10-29 |title=It turns out the closest exoplanet to us doesn't actually exist |magazine=Popular Mechanics |url=https://www.popularmechanics.com/space/a18003/no-alpha-centauri-b-planet/ |access-date=2018-12-08}}</ref><ref>{{cite news |title=Poof! The planet closest to our Solar system just vanished |date=2015-10-29 |website = National Geographic News |url=https://news.nationalgeographic.com/2015/10/151028-planet-disappears-alpha-centauri-astronomy-science/ |url-status=dead |access-date=2018-12-08 |archive-url=https://web.archive.org/web/20151030010115/http://news.nationalgeographic.com/2015/10/151028-planet-disappears-alpha-centauri-astronomy-science/ |archive-date=30 October 2015 }}</ref><ref name=Rajpaul2016>{{cite journal |first1=Vinesh |last1=Rajpaul |first2=Suzanne |last2=Aigrain |first3=Stephen J. |last3=Roberts |date=19 October 2015 |title=Ghost in the time series: No planet for {{nobr|alpha Cen B}} |journal=Monthly Notices of the Royal Astronomical Society |volume=456 |issue=1 |pages=L6–L10 |arxiv=1510.05598 |bibcode=2016MNRAS.456L...6R |doi=10.1093/mnrasl/slv164 |doi-access=free |s2cid=119294717}}</ref>

A search for [[astronomical transit|transits]] of planet Bb was conducted with the [[Hubble Space Telescope]] from 2013 to 2014. This search detected one potential transit-like event, which could be associated with a different planet with a radius around {{Earth radius|0.92|link=y}}. This planet would most likely orbit Alpha Centauri B with an orbital period of 20.4&nbsp;days or less, with only a 5% chance of it having a longer orbit. The median of the likely orbits is 12.4&nbsp;days. Its orbit would likely have an eccentricity of 0.24 or less.<ref name=Demory2015>{{cite journal |last1=Demory |first1=Brice-Olivier |last2=Ehrenreich |first2=David |last3=Queloz |first3=Didier |last4=Seager |first4=Sara |last5=Gilliland |first5=Ronald |last6=Chaplin |first6=William J. |last7=Proffitt |first7=Charles |last8=Gillon |first8=Michael |last9=Guenther |first9=Maximilian N. |last10=Benneke |first10=Bjoern |last11=Dumusque |first11=Xavier |last12=Lovis |first12=Christophe |last13=Pepe|first13=Francesco |last14=Segransan |first14=Damien |last15=Triaud |first15=Amaury |last16=Udry |first16=Stephane |display-authors=6 |date=June 2015 |title=Hubble Space Telescope search for the transit of the Earth-mass exoplanet Alpha Centauri Bb |journal=Monthly Notices of the Royal Astronomical Society |volume=450 |issue=2 |pages=2043–2051 |arxiv=1503.07528 |bibcode=2015MNRAS.450.2043D |doi=10.1093/mnras/stv673 |doi-access=free |s2cid=119162954}}</ref> It could have lakes of molten lava and would be far too close to Alpha Centauri B to harbour [[extraterrestrial life|life]].<ref>{{cite news |last=Aron |first=Jacob |title=Twin Earths may lurk in our nearest star system |magazine=[[New Scientist]] |url=https://www.newscientist.com/article/dn27259-twin-earths-may-lurk-in-our-nearest-star-system/ |access-date=2018-12-08}}</ref> If confirmed, this planet might be called {{nobr|Alpha Centauri Bc}}. However, the name has not been used in the literature, as it is not a claimed discovery.