Eta Muscae
{{Short description|Variable star in the constellation Musca}}
{{Starbox begin}}
{{Starbox image
| image = 250px
| caption = A light curve for Eta Muscae plotted from TESS data
}}
{{Starbox observe
| epoch = J2000.0
| constell = Musca
| dec = {{DEC|-67|53|40.5276}}
}}
{{Starbox character
| type =
| class = {{nowrap|B8V + sim. + K9.4XR? + A0p}} or {{nowrap|B7III + B7III}}
| u-b =
| variable = eclipsing binary
}}
{{Starbox astrometry
| parallax = 7.1001
| p_error = 0.1924
}}
{{Starbox orbit
| primary =
| name =
| period =
| period_unitless = 2.3963161 d
| axis =
| axis_unitless = {{Val|14.11|0.15|ul=solar radius}}
| eccentricity = 0.00
| inclination = 77.40
| node =
| periastron =
| periarg =
| periarg_primary =
| k1 = {{Val|145.35|0.20}}
| k2 = {{Val|145.38|0.20}}
}}
{{Starbox detail
| component1 = Eta Mus Aa
| mass = {{Val|3.30|0.04}}
| radius = {{Val|2.14|0.02}}
| luminosity = 223.77 (combined)
| temperature = {{Val|12700|100|fmt=commas}}
| gravity = {{Val|4.293|0.005}}
| metal_fe =
| rotational_velocity = {{Val|34|2}}
| age_gyr =
| component2 = Eta Mus Ab
| mass2 = {{Val|3.29|0.04}}
| radius2 = {{Val|2.13|0.04}}
| temperature2 = {{Val|12550|300|fmt=commas}}
| gravity2 = {{Val|4.298|0.005}}
| rotational_velocity2 = {{Val|44|2}}
}}
{{Starbox catalog
| names = {{odlist | B=η Mus | CPD=−67°2224 | FK5=493 | HD=114911 | HIP=64661 | HR=4993 | SAO=252224 | WDS=J13152-6754A }}
}}
{{Starbox reference
| Simbad = eta+Mus
}}
{{Starbox end}}
Eta Muscae is a multiple star system in the southern constellation of Musca. It is visible to the naked eye as a faint, blue-white hued point of light with an apparent visual magnitude of 4.79. The system is located around 406 light years away from the Sun. It is a member of the Lower Centaurs Crux subgroup of the Sco OB2 stellar association of co-moving stars.
The two main components of this system form a double-lined spectroscopic binary with a period of 2.4 days in a circular orbit. They are a detached eclipsing binary with a spectral type of B8V and a brightness that dips by 0.05 magnitude once per orbit. This pair consists of two components of similar mass and type.
Further away from the primary system are stars of magnitude 7.3 and 10, designated Eta Muscae B and C. It is unclear if these stars are gravitationally–bound to the main pair. Evidence for an additional component has been found with a 30-year cycle in the orbital behavior of the main pair. The data suggests an orbital eccentricity of 0.29 for this suspected component, Eta Muscae D.
References
{{reflist|refs=
{{cite simbad | title=eta Mus | access-date=2019-08-26 | postscript=. }}
| title=MAST: Barbara A. Mikulski Archive for Space Telescopes
| url=https://mast.stsci.edu/portal/Mashup/Clients/Mast/Portal.html
| publisher=Space Telescope Science Institute |access-date=8 December 2021}}
| title=η Muscae: a multiple system with a PMS component
| last1=Hensberge | first1=H. | last2=Nitschelm | first2=C.
| last3=Bouzid | first3=Y. M. | last4=Clausen | first4=V. J.
| last5=David | first5=M. | last6=Freyhammer | first6=M. L.
| last7=Helt | first7=B. | last8=Olsen | first8=H. E.
| last9=Sterken | first9=C. | last10=Vaz | first10=R. L. P.
| conference=Open Issues in Local Star Formation. Proceedings of the Ouro Preto Colloquium, Brazil
| editor1-first=Jacques | editor1-last=Lépine
| editor2-first=Jane | editor2-last=Gregorio-Hetem
| display-authors=1 | series=Astrophysics and Space Science Library
| volume=299 | date=April 5–10, 2003
| publisher=Kluwer Academic Publishers, Dordrecht
| bibcode=2003ASSL..299P...8H }}
| title=The Catalogue of Stellar Parameters from the Detached Double-Lined Eclipsing Binaries in the Milky Way
| last1=Eker | first1=Z. | last2=Bilir | first2=S.
| last3=Soydugan | first3=F. | last4=Gökçe | first4=E. Yaz
| last5=Soydugan | first5=E. | last6=Tüysüz | first6=M.
| last7=Şenyüz | first7=T. | last8=Demircan | first8=O.
| journal=Publications of the Astronomical Society of Australia
| volume=31 | id=e024 | pages=23 | date=May 2014
| doi=10.1017/pasa.2014.17 | arxiv=1403.1583
| display-authors=1 | bibcode=2014PASA...31...24E | s2cid=119238300 }}
| title=Three southern spectroscopic binaries
| last1=Buscombe | first1=W. | last2=Morris | first2=Pamela M.
| journal=Monthly Notices of the Royal Astronomical Society
| volume=123 | page=183 | date=1961
| issue=2 | doi=10.1093/mnras/123.2.183 | bibcode=1961MNRAS.123..183B | doi-access=free }}
| title=The AD binary in the multiple system eta Mus
| display-authors=1 | last1=Blackford | first1=M. G.
| last2=Butland | first2=R. J. | last3=Budding | first3=E.
| journal=Information Bulletin on Variable Stars
| volume=6171 | page=1 | date=June 2016
| bibcode=2016IBVS.6171....1B }}
| title=The radial velocities of 335 late B-type stars
| last1=Hube | first1=Douglas P.
| journal=Memoirs of the Royal Astronomical Society
| volume=72 | page=233 | date=1970
| bibcode=1970MmRAS..72..233H }}
| title=Triple System epsilon Vol and Quadruple System eta Mus: the Mass Ratio in Close Binary Systems
| last1=Medici | first1=A. | last2=Hubrig | first2=S.
| journal=Information Bulletin on Variable Stars
| volume=4827 | page=1 | date=January 2000
| bibcode=2000IBVS.4827....1M }}
| 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 | arxiv=1108.4971
| doi=10.1134/S1063773712050015 | s2cid=119257644 }}
| last1=Eggleton | first1=P. P. | last2=Tokovinin | first2=A. A.
| title=A catalogue of multiplicity among bright stellar systems
| journal=Monthly Notices of the Royal Astronomical Society
| volume=389 | issue=2 | pages=869–879 | date=September 2008
| bibcode=2008MNRAS.389..869E | arxiv=0806.2878
| doi=10.1111/j.1365-2966.2008.13596.x | doi-access=free | s2cid=14878976 }}
| first=F. | last=van Leeuwen
| title=Validation of the new Hipparcos reduction
| journal=Astronomy and Astrophysics
| volume=474 | issue=2 | pages=653–664 | date=November 2007
| bibcode=2007A&A...474..653V | arxiv=0708.1752
| doi=10.1051/0004-6361:20078357 | s2cid=18759600
}}
| title=Search for low-mass PMS companions around X-ray selected late B stars
| last1=Hubrig | first1=S. | last2=Le Mignant | first2=D.
| last3=North | first3=P. | last4=Krautter | first4=J.
| journal=Astronomy and Astrophysics | display-authors=1
| volume=372 | pages=152–164 | date=June 2001
| bibcode=2001A&A...372..152H | arxiv=astro-ph/0103201
| doi=10.1051/0004-6361:20010452 | s2cid=17507782 }}
| display-authors=1 | last1=Zasche | first1=P.
| last2=Wolf | first2=M. | last3=Hartkopf | first3=W. I.
| last4=Svoboda | first4=P. | last5=Uhlař | first5=R.
| last6=Liakos | first6=A. | last7=Gazeas | first7=K.
| title=A catalog of visual double and multiple stars with eclipsing components
| journal=The Astronomical Journal
| date=2009 | volume=138 | issue=2 | pages=664–79
| arxiv=0907.5172 | bibcode=2009AJ....138..664Z
| doi=10.1088/0004-6256/138/2/664 | s2cid=17089387 }}
}}
{{Musca|state=collapsed}}
{{DEFAULTSORT:Eta Muscae}}
Category:B-type main-sequence stars
Category:Spectroscopic binaries