Editing Libra (constellation) (section)

===Planetary systems===
Libra is home to the [[Gliese 581]] planetary system, which consists of the star Gliese 581 and three confirmed planets. This system gained attention in the late 2000s and early 2010s as the subject of some of the earliest claims of potentially habitable exoplanets,<ref>{{cite web|url=http://www.space.com/scienceastronomy/070424_hab_exoplanet.html|title=Major Discovery: New Planet Could Harbor Water and Life|website=space.com|date=24 April 2007 }}</ref><ref>{{Citation |last=Shiga |first=David |url=https://www.newscientist.com/article/dn19519-found-first-rocky-exoplanet-that-could-host-life.html |title=Found: first rocky exoplanet that could host life |publisher=[[New Scientist]]|date=September 29, 2010|access-date=September 30, 2010}}</ref> but it is now known that [[Gliese 581c]] is too hot to be potentially habitable, and the planet candidates [[Gliese 581d]] and [[Gliese 581g|g]] likely do not exist.<ref name="Robertson2014">{{cite journal |last1=Robertson |first1=Paul |author2-link=Suvrath Mahadevan |last2=Mahadevan |first2=Suvrath |last3=Endl |first3=Michael |last4=Roy |first4=Arpita |title=Stellar activity masquerading as planets in the habitable zone of the M dwarf Gliese 581 |journal=[[Science (journal)|Science]] |date=3 July 2014 |doi=10.1126/science.1253253 |pmid=24993348 |arxiv=1407.1049 |bibcode=2014Sci...345..440R |volume=345 |issue=6195 |pages=440–444 |citeseerx=10.1.1.767.2071 |s2cid=206556796 }}</ref> At the time of its discovery in 2009, [[Gliese 581e]] was the smallest mass [[exoplanet]] known orbiting a normal star.<ref name="mayor">{{cite journal |doi=10.1051/0004-6361/200912172 |bibcode=2009A&A...507..487M |journal=[[Astronomy and Astrophysics]] |volume=507 |issue=1 |year=2009 |pages=487–494 |last1=Mayor |first1=Michel |last2=Bonfils |first2=Xavier |last3=Forveille |first3=Thierry |last4=Delfosse |first4=Xavier |last5=Udry |first5=Stéphane |last6=Bertaux |first6=Jean-Loup |last7=Beust |first7=Hervé |last8=Bouchy |first8=François |last9=Lovis |first9=Christophe |last10=Pepe |first10=Francesco |last11=Perrier |first11=Christian |last12=Queloz |first12=Didier |last13=Santos |first13=Nuno C. |title=The HARPS search for southern extra-solar planets, XVIII. An Earth-mass planet in the GJ 581 planetary system |arxiv=0906.2780 |display-authors=3 |url=http://obswww.unige.ch/~udry/Gl581_preprint.pdf |s2cid=2983930 |url-status=dead |archive-url=https://web.archive.org/web/20090521052641/http://obswww.unige.ch/~udry/Gl581_preprint.pdf |archive-date=21 May 2009 }}</ref>