What is Mimosa (star)?
'''Mimosa''' is the second brightest object in the southern [[constellation]] of [[Crux]] after [[Alpha Crucis|Acrux]], and the [[List of brightest stars|21st brightest star]] in the night sky. It has the [[Bayer designation]] '''β Crucis''', which is '''Beta Crucis''' in Latin. Its name when shortened is '''Beta Cru''' or '''β Cru'''. Mimosa is part of the prominent [[Asterism (astronomy)|asterism]] called the [[Southern Cross]]. It is a [[binary star]] or a possible triple [[star system]]. It is also one of the closest stars with a [[infrared]] [[bow shock]]. [[File:Crux constellation map.png|thumb|The large dot in the cross at the left side labelled '''β''' is Mimosa.]] Based on [[parallax]] measurements, Mimosa is 277 [[light years]] from [[Earth]]. In 1957, German [[Astronomer|astronomor]] [[Wulff-Dieter Heintz]] discovered that it is a [[Binary star|spectroscopic binary]] with components that are too close together to resolve with a [[telescope]].<ref>{{Cite journal|last=Heintz|first=W. D.|date=1957-10-01|title=The radial velocity variation of beta Crucis|url=https://ui.adsabs.harvard.edu/abs/1957Obs....77..200H|journal=The Observatory|volume=77|pages=200|bibcode=1957Obs....77..200H |issn=0029-7704}}</ref> The pair orbit each other every five years with a guessed separation that changes from 5.4 to 12.0 [[Astronomical unit|AU]].<ref>{{Cite journal|last1=Aerts|first1=C.|last2=De Cat|first2=P.|last3=Cuypers|first3=J.|last4=Becker|first4=S. R.|last5=Mathias|first5=P.|last6=De Mey|first6=K.|last7=Gillet|first7=D.|last8=Waelkens|first8=C.|date=1998-01-01|title=Evidence for binarity and multiperiodicity in the beta Cephei star beta Crucis|url=https://ui.adsabs.harvard.edu/abs/1998A&A...329..137A|journal=Astronomy and Astrophysics|volume=329|pages=137–146|bibcode=1998A&A...329..137A |issn=0004-6361}}</ref> The age of the system is only 8 to 11 million years.<ref>{{Cite journal|last1=Cohen|first1=David H.|last2=Kuhn|first2=Michael A.|last3=Gagné|first3=Marc|last4=Jensen|first4=Eric L. N.|last5=Miller|first5=Nathan