# Alpha Muscae

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Star in the constellation Musca

Alpha Muscae Location of α Muscae (circled) Observation data Epoch J2000.0 Equinox J2000.0 Constellation Musca Right ascension 12h 37m 11.01789s[1] Declination −69° 08′ 08.0332″[1] Apparent magnitude (V) +2.69[2] Characteristics Evolutionary stage main sequence[3] Spectral type B2 IV–V[4] U−B color index −0.854[2] B−V color index −0.219[2] Variable type β Cep[5] Astrometry Radial velocity (Rv) +13[6] km/s Proper motion (μ) RA: −40.20[1] mas/yr Dec.: −12.80[1] mas/yr Parallax (π) 10.34±0.11 mas[1] Distance 315 ± 3 ly (97 ± 1 pc) Absolute magnitude (MV) −2.2[7] Details Mass 8.8±0.1[4] M☉ Radius 5.22 ± 0.06[8][a] R☉ Luminosity 4,270±100[8] L☉ Surface gravity (log g) 4.06[7] cgs Temperature 20,400[8] K Rotational velocity (v sin i) 114[9] km/s Age 18.3±3.2[4] Myr Other designations α Mus, CD−68 1104, CPD−68 1702, FK5 474, HD 109668, HIP 61585, HR 4798, SAO 251974[10] Database references SIMBAD data

**Alpha Muscae**, [Latinized](/source/Romanization_of_Greek) from α Muscae, is a [star](/source/Star) in the southern [circumpolar constellation](/source/Circumpolar_constellation) of [Musca](/source/Musca_(constellation)). With an [apparent visual magnitude](/source/Apparent_visual_magnitude) of +2.7,[2] it is the [brightest star](/source/List_of_stars_in_Musca) in the constellation. The distance to this star has been determined using [parallax](/source/Parallax) measurements, giving an estimate of about 315 [light-years](/source/Light-year) (97 [parsecs](/source/Parsec)) from Earth.[1]

With a [stellar classification](/source/Stellar_classification) of B2 IV-V,[4] this star appears to be in the process of [evolving](/source/Stellar_evolution) away from the [main sequence](/source/Main_sequence) of stars like the Sun and turning a [subgiant star](/source/Subgiant_star), as the supply of hydrogen at its core becomes exhausted. It is larger than the Sun, with nearly nine[4] times the mass and 5.2 times the radius.[a] This star is radiating around 4,300 times as much luminosity as the Sun from its outer atmosphere at an [effective temperature](/source/Effective_temperature) of 20,400 K,[7] giving it the blue-white hue of a [B-type star](/source/B-type_star).[11]

A [light curve](/source/Light_curve) for Alpha Muscae, plotted from *[TESS](/source/Transiting_Exoplanet_Survey_Satellite)* data[12]

Alpha Muscae appears to be a [Beta Cephei](/source/Beta_Cephei_variable) variable star. Telting and colleagues report it as a Beta Cephei with a high degree of confidence as they found regular pulsations in its spectrum in a high-resolution spectroscopy study published in 2006,[5] although Stankov and Handler (2005) listed it as a poor or rejected candidate in their *Catalog of Galactic β Cephei Stars*.[9] The [International Variable Star Index](/source/International_Variable_Star_Index) lists it as a Beta Cephei variable which varies in brightness from magnitude 2.68 to 2.73, with a period of 2.17 hours.[13] Alpha Muscae is rotating rapidly with a [projected rotational velocity](/source/Projected_rotational_velocity) of 114 km s−1[9] and has an estimated age of about 18 million years.[4]

This star is a [proper motion](/source/Proper_motion) member of the Lower Centaurus–Crux sub-group in the [Scorpius–Centaurus](/source/Scorpius%E2%80%93Centaurus_association) [OB association](/source/Stellar_association), the nearest such association of co-moving massive stars to the Sun.[7] Alpha Muscae has a [peculiar velocity](/source/Peculiar_velocity) of 10 km s−1, which, while high, is not enough for it to be considered a [runaway star](/source/Runaway_star).[4]

In the culture of the indigenous [Wardaman people](/source/Wardaman_people) of Australia, this star has the name Burangalul, referring to the "forehead band" of the [boomerang](/source/Boomerang) constellation Buran, which is equivalent to Musca.[14]

## Notes

1. ^ [***a***](#cite_ref-radius_9-0) [***b***](#cite_ref-radius_9-1) Calculated, using the [Stefan-Boltzmann law](/source/Stefan-Boltzmann_law) and the star's [effective temperature](/source/Effective_temperature) and luminosity, with respect to the [solar](/source/Sun) nominal effective temperature of 5,772 [K](/source/Kelvin): ( 5 , 772 20 , 400 ) 4 ⋅ 10 3.63 = 5.22 R ⊙ . {\displaystyle {\sqrt {{\biggl (}{\frac {5,772}{20,400}}{\biggr )}^{4}\cdot 10^{3.63}}}=5.22\ R_{\odot }.}

## References

1. ^ [***a***](#cite_ref-aaa474_2_653_1-0) [***b***](#cite_ref-aaa474_2_653_1-1) [***c***](#cite_ref-aaa474_2_653_1-2) [***d***](#cite_ref-aaa474_2_653_1-3) [***e***](#cite_ref-aaa474_2_653_1-4) [***f***](#cite_ref-aaa474_2_653_1-5) van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", *Astronomy and Astrophysics*, **474** (2): 653–664, [arXiv](/source/ArXiv_(identifier)):[0708.1752](https://arxiv.org/abs/0708.1752), [Bibcode](/source/Bibcode_(identifier)):[2007A&A...474..653V](https://ui.adsabs.harvard.edu/abs/2007A&A...474..653V), [doi](/source/Doi_(identifier)):[10.1051/0004-6361:20078357](https://doi.org/10.1051%2F0004-6361%3A20078357), [S2CID](/source/S2CID_(identifier)) [18759600](https://api.semanticscholar.org/CorpusID:18759600)

1. ^ [***a***](#cite_ref-apjs15_459_2-0) [***b***](#cite_ref-apjs15_459_2-1) [***c***](#cite_ref-apjs15_459_2-2) [***d***](#cite_ref-apjs15_459_2-3) Gutierrez-Moreno, Adelina; Moreno, Hugo (June 1968), "A photometric investigation of the Scorpio-Centaurus association", *Astrophysical Journal Supplement*, **15**: 459, [Bibcode](/source/Bibcode_(identifier)):[1968ApJS...15..459G](https://ui.adsabs.harvard.edu/abs/1968ApJS...15..459G), [doi](/source/Doi_(identifier)):[10.1086/190168](https://doi.org/10.1086%2F190168)

1. **[^](#cite_ref-jin2024_3-0)** Jin, Harim; Langer, Norbert; Lennon, Daniel J.; Proffitt, Charles R. (2024). "Boron depletion in Galactic early B-type stars reveals two different main sequence star populations". *Astronomy and Astrophysics*. **690**: A135. [arXiv](/source/ArXiv_(identifier)):[2405.18266](https://arxiv.org/abs/2405.18266). [Bibcode](/source/Bibcode_(identifier)):[2024A&A...690A.135J](https://ui.adsabs.harvard.edu/abs/2024A&A...690A.135J). [doi](/source/Doi_(identifier)):[10.1051/0004-6361/202450896](https://doi.org/10.1051%2F0004-6361%2F202450896).

1. ^ [***a***](#cite_ref-mnras410_1_190_4-0) [***b***](#cite_ref-mnras410_1_190_4-1) [***c***](#cite_ref-mnras410_1_190_4-2) [***d***](#cite_ref-mnras410_1_190_4-3) [***e***](#cite_ref-mnras410_1_190_4-4) [***f***](#cite_ref-mnras410_1_190_4-5) [***g***](#cite_ref-mnras410_1_190_4-6) 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](/source/Monthly_Notices_of_the_Royal_Astronomical_Society)*, **410** (1): 190–200, [arXiv](/source/ArXiv_(identifier)):[1007.4883](https://arxiv.org/abs/1007.4883), [Bibcode](/source/Bibcode_(identifier)):[2011MNRAS.410..190T](https://ui.adsabs.harvard.edu/abs/2011MNRAS.410..190T), [doi](/source/Doi_(identifier)):[10.1111/j.1365-2966.2010.17434.x](https://doi.org/10.1111%2Fj.1365-2966.2010.17434.x), [S2CID](/source/S2CID_(identifier)) [118629873](https://api.semanticscholar.org/CorpusID:118629873)

1. ^ [***a***](#cite_ref-aaa452_3_945_5-0) [***b***](#cite_ref-aaa452_3_945_5-1) Telting, J. H.; et al. (June 2006), "A high-resolution spectroscopy survey of β Cephei pulsations in bright stars", *Astronomy and Astrophysics*, **452** (3): 945–953, [Bibcode](/source/Bibcode_(identifier)):[2006A&A...452..945T](https://ui.adsabs.harvard.edu/abs/2006A&A...452..945T), [doi](/source/Doi_(identifier)):[10.1051/0004-6361:20054730](https://doi.org/10.1051%2F0004-6361%3A20054730), [hdl](/source/Hdl_(identifier)):[2066/36162](https://hdl.handle.net/2066%2F36162)

1. **[^](#cite_ref-rgcrv_6-0)** Evans, D. S. (June 20–24, 1966), Batten, Alan Henry; Heard, John Frederick (eds.), "The Revision of the General Catalogue of Radial Velocities", *Determination of Radial Velocities and Their Applications, Proceedings from IAU Symposium No. 30*, **30**, University of Toronto: [International Astronomical Union](/source/International_Astronomical_Union): 57, [Bibcode](/source/Bibcode_(identifier)):[1967IAUS...30...57E](https://ui.adsabs.harvard.edu/abs/1967IAUS...30...57E)

1. ^ [***a***](#cite_ref-aaa216_1_44_7-0) [***b***](#cite_ref-aaa216_1_44_7-1) [***c***](#cite_ref-aaa216_1_44_7-2) [***d***](#cite_ref-aaa216_1_44_7-3) de Geus, E. J.; de Zeeuw, P. T.; Lub, J. (June 1989), "Physical parameters of stars in the Scorpio-Centaurus OB association", *Astronomy and Astrophysics*, **216** (1–2): 44–61, [Bibcode](/source/Bibcode_(identifier)):[1989A&A...216...44D](https://ui.adsabs.harvard.edu/abs/1989A&A...216...44D)

1. ^ [***a***](#cite_ref-Sharma2022_8-0) [***b***](#cite_ref-Sharma2022_8-1) [***c***](#cite_ref-Sharma2022_8-2) Sharma, Awshesh N.; Bedding, Timothy R.; Saio, Hideyuki; White, Timothy R. (2022), "Pulsating B stars in the Scorpius–Centaurus Association with TESS", *Monthly Notices of the Royal Astronomical Society*, **515** (1): 828–840, [arXiv](/source/ArXiv_(identifier)):[2203.02582](https://arxiv.org/abs/2203.02582), [Bibcode](/source/Bibcode_(identifier)):[2022MNRAS.515..828S](https://ui.adsabs.harvard.edu/abs/2022MNRAS.515..828S), [doi](/source/Doi_(identifier)):[10.1093/mnras/stac1816](https://doi.org/10.1093%2Fmnras%2Fstac1816)

1. ^ [***a***](#cite_ref-apjss158_2_193_10-0) [***b***](#cite_ref-apjss158_2_193_10-1) [***c***](#cite_ref-apjss158_2_193_10-2) Stankov, Anamarija; Handler, Gerald (June 2005), "Catalog of Galactic β Cephei Stars", *The Astrophysical Journal Supplement Series*, **158** (2): 193–216, [arXiv](/source/ArXiv_(identifier)):[astro-ph/0506495](https://arxiv.org/abs/astro-ph/0506495), [Bibcode](/source/Bibcode_(identifier)):[2005ApJS..158..193S](https://ui.adsabs.harvard.edu/abs/2005ApJS..158..193S), [doi](/source/Doi_(identifier)):[10.1086/429408](https://doi.org/10.1086%2F429408), [S2CID](/source/S2CID_(identifier)) [119526948](https://api.semanticscholar.org/CorpusID:119526948)

1. **[^](#cite_ref-SIMBAD_11-0)** ["HD 109668 -- Variable Star of Beta Cep type"](http://simbad.u-strasbg.fr/sim-id.pl?protocol=html&Ident=alpha+muscae), *SIMBAD Astronomical Database*, retrieved 2007-01-29

1. **[^](#cite_ref-csiro_12-0)** ["The Colour of Stars"](https://web.archive.org/web/20041108073631/http://outreach.atnf.csiro.au/education/senior/astrophysics/photometry_colour.html), *Australia Telescope, Outreach and Education*, [Commonwealth Scientific and Industrial Research Organisation](/source/Commonwealth_Scientific_and_Industrial_Research_Organisation), December 21, 2004, archived from [the original](http://outreach.atnf.csiro.au/education/senior/astrophysics/photometry_colour.html) on November 8, 2004, retrieved 2012-01-16

1. **[^](#cite_ref-MAST_13-0)** ["MAST: Barbara A. Mikulski Archive for Space Telescopes"](https://mast.stsci.edu/portal/Mashup/Clients/Mast/Portal.html). Space Telescope Science Institute. Retrieved 8 December 2021.

1. **[^](#cite_ref-IVSI_14-0)** ["alf Mus"](https://www.aavso.org/vsx/index.php?view=detail.top&oid=19955). *The International Variable Star Index*. AAVSO. Retrieved 16 December 2022.

1. **[^](#cite_ref-ASE_15-0)** ["Burangalul"](https://ase.exopla.net/index.php/Burangalul). *All Skies Encyclopaedia*. [IAU Working Group on Star Names](/source/IAU_Working_Group_on_Star_Names). Retrieved 1 July 2025.

v t e Constellation of Musca List of stars in Musca Musca in Chinese astronomy Stars Bayer α β γ δ ε ζ1 ζ2 η θ ι1 ι2 λ μ λ Cha Variable R S SY TU GQ GR GU GT KR MP V357 HR 4538 4549 5002 HD 111232 112410 Other Gliese 440 PSR J1141−6545 YSES 1 YSES 2 YSES 2b Exoplanets HD 111232 b Star clusters NGC 4372 NGC 4463 NGC 4815 NGC 4833 Nebulae NGC 5189 Other BHR 71 Dark Doodad Nebula Engraved Hourglass Nebula G299.2-2.9 Category

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Adapted from the Wikipedia article [Alpha Muscae](https://en.wikipedia.org/wiki/Alpha_Muscae) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Alpha_Muscae?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.