Eta Muscae

{{Short description|Variable star in the constellation Musca}} {{Starbox begin}} {{Starbox image | image = {{Location mark |image=Musca constellation map.svg|alt=|float=center|width=280 |label=|position=right |mark=Red circle.svg|mark_width=10|mark_link=η Muscae |x=355|y=325 }} | caption = Location of η Muscae (circled in red) }} {{Starbox observe | epoch = [[J2000.0]] | equinox = [[J2000.0]] ([[International Celestial Reference System|ICRS]]) | constell = [[Musca (constellation)|Musca]] | ra = {{RA|13|15|14.94123}}<ref name=vanLeeuwen2007/> | dec = {{DEC|-67|53|40.5276}}<ref name=vanLeeuwen2007/> | appmag_v = 4.79<ref name=Anderson2012/> }} {{Starbox character | type = | class = {{nowrap|B8V + sim. + K9.4XR? + A0p}}<ref name=Eggleton2008/> or {{nowrap|B7III + B7III}}<ref name=Hube1970/> | b-v = {{Val|−0.078|0.003}}<ref name=Anderson2012/> | u-b = | variable = eclipsing binary }} {{Starbox astrometry | radial_v = {{Val|−8.1|7.4}}<ref name=Anderson2012/> | prop_mo_ra = +30.207<ref name=vanLeeuwen2007/> | prop_mo_dec = +17.921<ref name=vanLeeuwen2007/> | parallax = 7.1001 | p_error = 0.1924 | parallax_footnote = <ref name=vanLeeuwen2007/> | dist_ly = 405.7<ref name=Hubrig2001/> | dist_pc = 124.4<ref name=Hubrig2001/> | absmag_v = −0.81<ref name=Hubrig2001/> }} {{Starbox orbit | reference = <ref name=Eker2014/> | 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 | source = <ref name=Eker2014/> | component1 = Eta Mus Aa | mass = {{Val|3.30|0.04}} | radius = {{Val|2.14|0.02}} | luminosity = 223.77<ref name=Anderson2012/> (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 }}<ref name=SIMBAD/> }} {{Starbox reference | Simbad = eta+Mus }} {{Starbox end}}

'''Eta Muscae''' is a multiple<ref name=Butland2011/><ref name=Medici2000/> [[star]] system in the southern [[constellation]] of [[Musca (constellation)|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.<ref name=Anderson2012/> The system is located around 406 [[light year]]s away from the Sun.<ref name=Hubrig2001/> It is a member of the Lower Centaurs Crux subgroup of the [[Sco OB2]] stellar association of co-moving stars.<ref name=Hensberge2003/>

The two main components of this system form a double-lined [[spectroscopic binary]]<ref name=Buscombe1961/> with a [[orbital period|period]] of 2.4 days in a circular orbit.<ref name=Eker2014/><ref name=Hensberge2003/> They are a detached [[eclipsing binary]] with a spectral type of B8V and a brightness that dips by 0.05 magnitude once per orbit.<ref name=Zasche09/> This pair consists of two components of similar mass and type.<ref name=Eggleton2008/>

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.<ref name=Butland2011/> The data suggests an [[orbital eccentricity]] of 0.29 for this suspected component, Eta Muscae D.<ref name=Blackford2016/> {{clear left}} ==References== <references>

<ref name=SIMBAD>{{cite simbad | title=eta Mus | access-date=2019-08-26 | postscript=. }}</ref>

<ref name=MAST>{{cite web | 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}}</ref>

<ref name=Hensberge2003>{{cite conference | 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 }}</ref>

<ref name=Eker2014>{{cite journal | 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 }}</ref>

<ref name=Buscombe1961>{{cite journal | 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 }}</ref>

<ref name=Blackford2016>{{cite journal | 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 }}</ref>

<ref name=Hube1970>{{cite journal | 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 }}</ref>

<ref name=Medici2000>{{cite journal | 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 }}</ref>

<ref name=Anderson2012>{{cite journal | 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 }}</ref>

<ref name=Eggleton2008>{{cite journal | 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 }}</ref>

<ref name=vanLeeuwen2007>{{cite journal | 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 }}</ref>

<ref name=Hubrig2001>{{cite journal | 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 }}</ref>

<ref name=Zasche09>{{cite journal | 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 }}</ref>

<ref name=Butland2011>{{cite journal | last1=Butland | first1=R. J. | last2=Budding | first2=E. | title=Another component in the multiple system Eta Mus | journal=Commissions 27 and 42 of the IAU Information Bulletin on Variable Stars | date=2011 | volume=6004 | issue=6004 | page=1 | bibcode=2011IBVS.6004....1B | url=http://www.konkoly.hu/cgi-bin/IBVS?6004 | archive-url=https://archive.today/20131221150808/http://www.konkoly.hu/cgi-bin/IBVS?6004 | url-status=dead | archive-date=December 21, 2013 }}</ref>

</references>

{{Musca|state=collapsed}}  [[Category:B-type main-sequence stars]] [[Category:Lower Centaurus Crux]] [[Category:Spectroscopic binaries]] [[Category:Eclipsing binaries]]  [[Category:Musca]] [[Category:Bayer objects|Muscae, Eta]] [[Category:Durchmusterung objects|PD-67 02224]] [[Category:Henry Draper Catalogue objects|114911]] [[Category:Hipparcos objects|64661]] [[Category:Bright Star Catalogue objects|4993]]