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Alpha Muscae
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| 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 from α Muscae, is a star in the southern circumpolar constellation of Musca. With an apparent visual magnitude of +2.7,[2] it is the brightest star in the constellation. The distance to this star has been determined using parallax measurements, giving an estimate of about 315 light-years (97 parsecs) from Earth.[1]
With a stellar classification of B2 IV-V,[4] this star appears to be in the process of evolving away from the main sequence of stars like the Sun and turning a 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 of 20,400 K,[7] giving it the blue-white hue of a B-type star.[11]
Alpha Muscae appears to be a Beta Cephei 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 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 of 114 km s−1[9] and has an estimated age of about 18 million years.[4]
This star is a proper motion member of the Lower Centaurus–Crux sub-group in the Scorpius–Centaurus OB association, the nearest such association of co-moving massive stars to the Sun.[7] Alpha Muscae has a peculiar velocity of 10 km s−1, which, while high, is not enough for it to be considered a runaway star.[4]
In the culture of the indigenous Wardaman people of Australia, this star has the name Burangalul, referring to the "forehead band" of the boomerang constellation Buran, which is equivalent to Musca.[14]
Notes
[edit]- ^ a b Calculated, using the Stefan-Boltzmann law and the star's effective temperature and luminosity, with respect to the solar nominal effective temperature of 5,772 K:
References
[edit]- ^ 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 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
- ^ 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:2405.18266. Bibcode:2024A&A...690A.135J. doi:10.1051/0004-6361/202450896.
- ^ a b c d e f g 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
- ^ a b 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:2006A&A...452..945T, doi:10.1051/0004-6361:20054730, hdl:2066/36162
- ^ 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: 57, Bibcode:1967IAUS...30...57E
- ^ a b c d 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:1989A&A...216...44D
- ^ a b c 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:2203.02582, Bibcode:2022MNRAS.515..828S, doi:10.1093/mnras/stac1816
- ^ a b c Stankov, Anamarija; Handler, Gerald (June 2005), "Catalog of Galactic β Cephei Stars", The Astrophysical Journal Supplement Series, 158 (2): 193–216, arXiv:astro-ph/0506495, Bibcode:2005ApJS..158..193S, doi:10.1086/429408, S2CID 119526948
- ^ "HD 109668 -- Variable Star of Beta Cep type", SIMBAD Astronomical Database, retrieved 2007-01-29
- ^ "The Colour of Stars", Australia Telescope, Outreach and Education, Commonwealth Scientific and Industrial Research Organisation, December 21, 2004, archived from the original on November 8, 2004, retrieved 2012-01-16
- ^ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 8 December 2021.
- ^ "alf Mus". The International Variable Star Index. AAVSO. Retrieved 16 December 2022.
- ^ "Burangalul". All Skies Encyclopaedia. IAU Working Group on Star Names. Retrieved 1 July 2025.
