Beta Muscae

Beta Muscae
	Location of β Musca (circled)
Observation data; Epoch J2000.0 Equinox J2000.0 (ICRS)
Constellation	Musca
Right ascension	12h 46m 16.80410s
Declination	−68° 06′ 29.2164″
Apparent magnitude (V)	3.05 (3.51 + 4.01)
Characteristics
Spectral type	B2 V + B3 V
U−B color index	−0.766
B−V color index	−0.198
Astrometry
Radial velocity (Rv)	+42 km/s
Proper motion (μ)	RA: −41.97 mas/yr ; Dec.: −8.89 mas/yr
Parallax (π)	9.55±0.41 mas
Distance	340 ± 10 ly ; (105 ± 4 pc)
Absolute magnitude (MV)	−2.06
Orbit
Period (P)	194.28 yr
Semi-major axis (a)	0.969″
Eccentricity (e)	0.598
Inclination (i)	37.1°
Longitude of the node (Ω)	349.4°
Periastron epoch (T)	1857.50
Argument of periastron (ω); (secondary)	209.0°
Details
β Mus A
Mass	7.35 M☉
Radius	3.5 R☉
Luminosity	2,750 L☉
Temperature	22,500 K
Age	15.1±1.2 Myr
β Mus B
Mass	6.40 M☉
Radius	3.5 R☉
Luminosity	1,200 L☉
Temperature	18,500 K
Other designations
	β Mus, CPD−67 2064, HD 110879, HIP 62322, HR 4844, SAO 252019
Database references
SIMBAD	data

Beta Muscae, Latinized from β Muscae, is a binary star in the southern circumpolar constellation of Musca. With a combined apparent visual magnitude of 3.07,^[2] it is the second brightest star (or star system) in the constellation. Judging by the parallax results, it is located at a distance of roughly 340 ± 13 light-years (105 ± 4 parsecs) from the Earth.^[1]

This is a binary star system with a period of about 194 years at an orbital eccentricity of 0.6.^[6] As of 2007, the two stars had an angular separation of 1.206 arcseconds at a position angle of 35°.^[7] The components are main sequence stars of similar size and appearance. The primary component, β Muscae A, has an apparent magnitude of 3.51, a stellar classification of B2 V,^[2] and about 7.35 times the Sun's mass.^[7] The secondary component, β Muscae B, has an apparent magnitude of 4.01, a stellar classification of B3 V,^[2] and is about 6.40 times the mass of the Sun.^[7]

This is a confirmed member of the Scorpius–Centaurus association,^[2]^[7] which is a group of stars with similar ages, locations, and trajectories through space, implying that they formed together in the same molecular cloud. Beta Muscae is considered a runaway star system as it has a high peculiar velocity of 43.9 km s⁻¹ relative to the normal galactic rotation. Runaway stars can be produced through several means, such as through an encounter with another binary star system. Binary systems form a relatively small fraction of the total population of runaway stars.^[11]

References

^ ^a ^b ^c ^d ^e ^f van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357, S2CID 18759600
^ ^a ^b ^c ^d ^e ^f Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976
^ ^a ^b Gutierrez-Moreno, Adelina; Moreno, Hugo (June 1968), "A Photometric Investigation of the Scorpio-Centaurus Association", Astrophysical Journal Supplement, 15: 459, Bibcode:1968ApJS...15..459G, doi:10.1086/190168
^ Wilson, Ralph Elmer (1953), "General Catalogue of Stellar Radial Velocities", Carnegie Institute Washington D.C. Publication, Washington: Carnegie Institution of Washington, Bibcode:1953GCRV..C......0W.
^ Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID 119257644.
^ ^a ^b "Sixth Catalog of Orbits of Visual Binary Stars", U.S. Naval Observatory, archived from the original on 2009-04-12, retrieved 2008-06-22
^ ^a ^b ^c ^d ^e ^f Kouwenhoven, M. B. N.; Brown, A. G. A.; Portegies Zwart, S. F.; Kaper, L. (October 2007), "The primordial binary population. II. Recovering the binary population for intermediate mass stars in Scorpius OB2", Astronomy and Astrophysics, 474 (1): 77–104, arXiv:0707.2746, Bibcode:2007A&A...474...77K, doi:10.1051/0004-6361:20077719, S2CID 15750945
^ ^a ^b ^c ^d ^e ^f "Beta Muscae", stars.astro.illinois.edu, retrieved 2025-07-13.
^ Tetzlaff, N.; Neuhäuser, R.; Hohle, M. M. (January 2011), "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun", Monthly Notices of the Royal Astronomical Society, 410 (1): 190–200, arXiv:1007.4883, Bibcode:2011MNRAS.410..190T, doi:10.1111/j.1365-2966.2010.17434.x, S2CID 118629873
^ "CCDM J12463-6806AB -- Double or multiple star", SIMBAD, Centre de Données astronomiques de Strasbourg, retrieved 2012-01-20
^ Hoogerwerf, R.; de Bruijne, J. H. J.; de Zeeuw, P. T. (January 2001), "On the origin of the O and B-type stars with high velocities. II. Runaway stars and pulsars ejected from the nearby young stellar groups", Astronomy and Astrophysics, 365 (2): 49–77, arXiv:astro-ph/0010057, Bibcode:2001A&A...365...49H, doi:10.1051/0004-6361:20000014, S2CID 18970167

[aaa474_2_653-1] ^ ^a ^b ^c ^d ^e ^f van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357, S2CID 18759600

[mnras389_2_869-2] ^ ^a ^b ^c ^d ^e ^f Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976

[apjs15_459-3] Gutierrez-Moreno, Adelina; Moreno, Hugo (June 1968), "A Photometric Investigation of the Scorpio-Centaurus Association", Astrophysical Journal Supplement, 15: 459, Bibcode:1968ApJS...15..459G, doi:10.1086/190168

[gcsrv-4] Wilson, Ralph Elmer (1953), "General Catalogue of Stellar Radial Velocities", Carnegie Institute Washington D.C. Publication, Washington: Carnegie Institution of Washington, Bibcode:1953GCRV..C......0W.

[Anderson2012-5] Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID 119257644.

[scovb-6] "Sixth Catalog of Orbits of Visual Binary Stars", U.S. Naval Observatory, archived from the original on 2009-04-12, retrieved 2008-06-22

[aaa474_1_77-7] ^ ^a ^b ^c ^d ^e ^f Kouwenhoven, M. B. N.; Brown, A. G. A.; Portegies Zwart, S. F.; Kaper, L. (October 2007), "The primordial binary population. II. Recovering the binary population for intermediate mass stars in Scorpius OB2", Astronomy and Astrophysics, 474 (1): 77–104, arXiv:0707.2746, Bibcode:2007A&A...474...77K, doi:10.1051/0004-6361:20077719, S2CID 15750945

[kaler-8] ^ ^a ^b ^c ^d ^e ^f "Beta Muscae", stars.astro.illinois.edu, retrieved 2025-07-13.

[mnras410_1_190-9] Tetzlaff, N.; Neuhäuser, R.; Hohle, M. M. (January 2011), "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun", Monthly Notices of the Royal Astronomical Society, 410 (1): 190–200, arXiv:1007.4883, Bibcode:2011MNRAS.410..190T, doi:10.1111/j.1365-2966.2010.17434.x, S2CID 118629873

[SIMBAD-10] "CCDM J12463-6806AB -- Double or multiple star", SIMBAD, Centre de Données astronomiques de Strasbourg, retrieved 2012-01-20

[aaa365_49-11] Hoogerwerf, R.; de Bruijne, J. H. J.; de Zeeuw, P. T. (January 2001), "On the origin of the O and B-type stars with high velocities. II. Runaway stars and pulsars ejected from the nearby young stellar groups", Astronomy and Astrophysics, 365 (2): 49–77, arXiv:astro-ph/0010057, Bibcode:2001A&A...365...49H, doi:10.1051/0004-6361:20000014, S2CID 18970167

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Beta Muscae

References

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