{{Short description|Star in the constellation Crux}} {{Starbox begin}} {{Starbox image | image = {{Location mark |image=Crux constellation map.svg|alt=|float=center|width=280 |label=|position=right |mark=Red circle.svg|mark_width=10|mark_link=μ Crucis |x=595|y=358 }} | caption = Location of μ Crucis (circled in red) }} {{Starbox observe 2s | epoch=J2000 | equinox= | constell=Crux | component1=μ<sup>1</sup> Crucis | ra1={{RA|12|54|35.6249}}<ref name=aaa323/> | dec1={{DEC|-57|10|40.527}}<ref name=aaa323/> | appmag_v1=4.03<ref name=clpl4/> | component2=μ<sup>2</sup> Crucis | ra2={{RA|12|54|36.8865}}<ref name=aaa323/> | dec2={{DEC|−57|10|07.214}}<ref name=aaa323/> | appmag_v2=5.19<ref name=clpl4/> }} {{Starbox character | component1=μ<sup>1</sup> Cru | type = subgiant<ref name=Aschenbrenner2026/> | class=B2IV-V<ref name=hiltner/> | b-v=−0.17<ref name=clpl4/> | u-b=−0.75<ref name=clpl4/> | variable= | component2=μ<sup>2</sup> Cru | class2=B5Vne<ref name=mk/> | b-v2=−0.11<ref name=clpl4/> | u-b2=−0.50<ref name=clpl4/> | variable2= }} {{Starbox astrometry | component1 = μ<sup>1</sup> Cru | radial_v=+13.9<ref name=rgcrv/> | prop_mo_ra=−30.45<ref name=aaa323/> | prop_mo_dec=−13.55<ref name=aaa323/> | parallax=9.6267 | p_error=0.3611 | parallax_footnote=<ref name=dr2a/> | dist_pc = {{Val|113|7|6}} | dist_ly = {{val|{{convert|113|pc|ly|disp=number}}|{{convert|7|pc|ly|disp=number}}|{{convert|6|pc|ly|disp=number}}}} | dist_footnote = <ref name=Aschenbrenner2026/> | absmag_v=−1.49<ref name=Anderson2012/> | component2 = μ<sup>2</sup> Cru | radial_v2=+13<ref name=rgcrv/> | prop_mo_ra2=−32.35<ref name=aaa323/> | prop_mo_dec2=−10.93<ref name=aaa323/> | parallax2=8.9486 | p_error2=0.2264 | parallax_footnote2=<ref name=dr2b/> | absmag_v2=−0.40<ref name=Anderson2012/> }} {{Starbox detail | component1 = μ<sup>1</sup> Cru | mass={{Val|7.0|0.1}}<ref name=Aschenbrenner2026/> | radius={{Val|3.3|0.2}}<ref name=Aschenbrenner2026/> | luminosity={{Val|1740|170|150|fmt=commas}}<ref name=Aschenbrenner2026/> | temperature={{Val|20500|250|fmt=commas}}<ref name=Aschenbrenner2026/> | gravity = {{Val|4.25|0.05}}<ref name=Aschenbrenner2026/> | metal_fe=−0.21<ref name=Anderson2012/> | rotation= | rotational_velocity={{Val|31.3|0.2}}<ref name=Aschenbrenner2026/> | age_myr={{Val|9.5|5.6|5.3}}<ref name=Aschenbrenner2026/> | component2 = μ<sup>2</sup> Cru | mass2=5.0<ref name=tetzlaff/> | radius2=3.9<ref name=zorec/> | luminosity2 = 205<ref name=Anderson2012/> | temperature2 = 20,400<ref name=zorec/> | gravity2 = 3.40<ref name=chauville/> | rotational_velocity2 = 210<ref name=chauville/> | age_myr2=15.9<ref name=tetzlaff/> }} {{Starbox catalog | names=μ Cru, WD 12546-5711, CCDM 12546-5711<ref name=simbad1/><ref name=simbad2/> | component1 = μ<sup>1</sup> Cru | names1=HR 4898, CD−56°4688, HD 112092, SAO 240366, HIP 63003 | component2 = μ<sup>2</sup> Cru | names2=HR 4899, CD−56°4689, HD 112091, SAO 240367, HIP 63005 }} {{Starbox reference | Simbad = mu+Cru|sn=μ Cru | Simbad2 = mu1+Cru|sn2=μ<sup>1</sup> Cru | Simbad3 = mu2+Cru|sn3=μ<sup>2</sup> Cru }}{{Starbox end}}
'''Mu Crucis''', Latinized from μ Crucis, is the seventh-brightest star in the constellation Crux commonly known as the Southern Cross. μ Crucis is a wide double star of spectral class B stars, magnitude 4.0 and 5.2 respectively. They lie about 370 light-years away, and both stars are likely physically attached. The brighter component is known as μ<sup>1</sup> Crucis or μ Crucis A, while the fainter is μ<sup>2</sup> Crucis or μ Crucis B.
μ<sup>1</sup> Crucis is the brighter of the two stars with an apparent magnitude of 4.0. It is a hot massive main sequence or subgiant star, over a thousand times as luminous as the sun.
μ<sup>2</sup> Crucis is the fainter of the pair. Its apparent magnitude is 5.2 and it is a Be star, a star spinning so quickly that it has ejected a disc of material that creates emission lines in its spectrum. The disc is inclined at 36° to our line of sight.<ref name=zorec/>
==References== <references>
<ref name="aaa323">{{cite journal | last=Perryman | first=M. A. C. |display-authors=etal | title=The HIPPARCOS Catalogue | journal=Astronomy & Astrophysics | volume=323 | pages=L49–L52 |date=April 1997 | bibcode=1997A&A...323L..49P }}</ref>
<ref name=Anderson2012>{{citation | title=XHIP: An extended hipparcos compilation | last1=Anderson | first1=E. | last2=Francis | first2=Ch. | journal=Astronomy Letters | volume=38 | issue=5 | pages=331 | year=2012 | bibcode=2012AstL...38..331A | doi=10.1134/S1063773712050015 | arxiv=1108.4971 | s2cid=119257644 | postscript=. }}</ref>
<ref name="simbad1">{{cite simbad | title=HR 4898 | access-date=2010-06-08 }}</ref>
<ref name="simbad2">{{cite simbad | title=HIP 63005 | access-date=2010-06-08 }}</ref>
<ref name="rgcrv">{{cite conference |last=Evans |first=D. S. |date=June 20–24, 1966 |editor1=Batten, Alan Henry |editor2=Heard, John Frederick |title=The Revision of the General Catalogue of Radial Velocities |book-title=Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30 |location=University of Toronto |publisher=International Astronomical Union |bibcode=1967IAUS...30...57E }}</ref>
<ref name=Aschenbrenner2026>{{cite journal |last=Aschenbrenner |first=P. |last2=Przybilla |first2=N. |title=Quantitative spectroscopy of single and multiple OB-type stars. Non-LTE spectrum analysis with machine learning |date=2026-04-03 |journal=Astronomy and Astrophysics |arxiv=2604.03082}}</ref>
<ref name="clpl4">{{cite journal | author=Johnson, H. L. |author2=Iriarte, B. |author3=Mitchell, R. I. |author4=Wisniewskj, W. Z. | title=UBVRIJKL photometry of the bright stars | journal=Communications of the Lunar and Planetary Laboratory | volume=4 | issue=99 | date=1966 |page=99 | bibcode=1966CoLPL...4...99J }}</ref>
<ref name=tetzlaff>{{cite journal|bibcode=2011MNRAS.410..190T|title=A catalogue of young runaway Hipparcos stars within 3 KPC from the Sun|journal=Monthly Notices of the Royal Astronomical Society|volume=410|issue=1|pages=190|last1=Tetzlaff|first1=N.|last2=Neuhäuser|first2=R.|last3=Hohle|first3=M. M.|year=2011|arxiv=1007.4883|doi=10.1111/j.1365-2966.2010.17434.x|doi-access=free |s2cid=118629873}}</ref>
<ref name=chauville>{{cite journal|bibcode=2001A&A...378..861C|title=High and intermediate-resolution spectroscopy of be stars 4481 lines|journal=Astronomy and Astrophysics|volume=378|pages=861|last1=Chauville|first1=J.|last2=Zorec|first2=J.|last3=Ballereau|first3=D.|last4=Morrell|first4=N.|last5=Cidale|first5=L.|last6=Garcia|first6=A.|year=2001|doi=10.1051/0004-6361:20011202|url=https://ri.conicet.gov.ar/bitstream/11336/36962/2/CONICET_Digital_Nro.da657706-52b0-4788-843c-67c34222e14c_A.pdf|doi-access=free}}</ref>
<ref name=zorec>{{cite journal|doi=10.1051/0004-6361:20066615|title=Be star disc characteristics near the central object|journal=Astronomy & Astrophysics|volume=470|issue=1|pages=239–247|year=2007|last1=Zorec|first1=J.|last2=Arias|first2=M. L.|last3=Cidale|first3=L.|last4=Ringuelet|first4=A. E.|bibcode=2007A&A...470..239Z|doi-access=free|hdl=11336/38181|hdl-access=free}}</ref>
<ref name=mk>{{cite journal|bibcode=2006MNRAS.371..252L|title=Spectroscopic analysis of southern B and be stars|journal=Monthly Notices of the Royal Astronomical Society|volume=371|issue=1|pages=252–262|last1=Levenhagen|first1=R. S.|last2=Leister|first2=N. V.|year=2006|arxiv=astro-ph/0606149|doi=10.1111/j.1365-2966.2006.10655.x|doi-access=free |s2cid=16492030}}</ref>
<ref name=hiltner>{{cite journal|bibcode=1969ApJ...157..313H|title=MK Spectral Types for Bright Southern OB Stars|journal=The Astrophysical Journal|volume=157|pages=313|last1=Hiltner|first1=W. A.|last2=Garrison|first2=R. F.|last3=Schild|first3=R. E.|year=1969|doi=10.1086/150069|doi-access=free}}</ref>
<ref name=dr2a>{{cite DR2|6060547163653418112}}</ref>
<ref name=dr2b>{{cite DR2|6060547331128876928}}</ref>
</references>
{{Stars of Crux}}
Category:Binary stars Crucis, Mu Category:Crux Category:B-type main-sequence stars Category:B-type subgiants Category:Lower Centaurus Crux 4898 112091 2 063003 5 CD-56 04688 9 Category:Be stars