Astronomy:Mu Velorum
Mu Velorum (μ Vel, μ Velorum) is a binary star system in the southern constellation Vela. The pair have a combined apparent visual magnitude of 2.69,[2] making the system readily visible to the naked eye. From parallax measurements, the distance to this system is measured at 117 light-years (36 parsecs).[1]
Characteristics
The two stars orbit each other with an period of 138 years and a very high eccentricity of 0.94. Their semi-major axis is of 50 astronomical units,[lower-alpha 1] but due to this high eccentricity the separation at periastron is just 3.1 au, while at the apoastron their separation is about 100 au.[lower-alpha 2] The system is about 360 million years old.[3]
The primary component is a giant star with an apparent magnitude of 2.7 and a stellar classification of G5 III.[3] It is radiating about 107 times the luminosity of the Sun from an expanded atmosphere about 13 times the Sun's radius.[8] The mass of this star is 3.3 times that of the Sun.[7] In 1998, the Extreme Ultraviolet Explorer space telescope detected a strong flare that released an X-ray emission nearly equal to the output of the entire star. The quiescent X-ray luminosity of Mu Velorum A is about 1.7 × 1030 erg s−1.[3]
The fainter companion, Mu Velorum B, is a main sequence star with an apparent magnitude of 6.4[3] and an assigned stellar classification of G2V.[3] However, this classification is suspect. Closer examination of the spectrum suggests the star may actually have a classification of F4V or F5V, which suggests a mass of about 1.5 times the mass of the Sun. Such stars typically do not show a marked level of magnetic activity.[3]
Notes
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, doi:10.1051/0004-6361:20078357, Bibcode: 2007A&A...474..653V.
- ↑ 2.0 2.1 2.2 2.3 Johnson, H. L. et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory 4 (99): 99, Bibcode: 1966CoLPL...4...99J.
- ↑ 3.00 3.01 3.02 3.03 3.04 3.05 3.06 3.07 3.08 3.09 3.10 3.11 3.12 Ayres, Thomas R.; Osten, Rachel A.; Brown, Alexander (November 1999), "The Rise and Fall of μ Velorum: A Remarkable Flare on a Yellow Giant Star Observed with the Extreme Ultraviolet Explorer", The Astrophysical Journal 526 (1): 445–450, doi:10.1086/308001, Bibcode: 1999ApJ...526..445A.
- ↑ Evans, D. S. (June 20–24, 1966), "The Revision of the General Catalogue of Radial Velocities", in Batten, Alan Henry; Heard, John Frederick, Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30, 30, University of Toronto: International Astronomical Union, p. 57, Bibcode: 1967IAUS...30...57E.
- ↑ Cardini, D. (January 2005), "Mg II chromospheric radiative loss rates in cool active and quiet stars", Astronomy and Astrophysics 430: 303–311, doi:10.1051/0004-6361:20041440, Bibcode: 2005A&A...430..303C.
- ↑ 6.0 6.1 Izmailov, Igor; Khovritchev, Maxim (January 2025), "New Orbital Parameters of 850 Wide Visual Binary Stars and Their Statistical Properties" (in en), Research in Astronomy and Astrophysics 25 (1): 015016, doi:10.1088/1674-4527/ad9da3, ISSN 1674-4527, Bibcode: 2025RAA....25a5016I.
- ↑ 7.0 7.1 7.2 7.3 7.4 Mallik, Sushma V.; Parthasarathy, M.; Pati, A. K. (October 2003), "Lithium and rotation in F and G dwarfs and subgiants", Astronomy and Astrophysics 409: 251–261, doi:10.1051/0004-6361:20031084, Bibcode: 2003A&A...409..251M.
- ↑ 8.0 8.1 Mullan, D. J. et al. (May 2006), "A Comparative Study of Flaring Loops in Active Stars", The Astrophysical Journal Supplement Series 164 (1): 173–201, doi:10.1086/502629, Bibcode: 2006ApJS..164..173M, http://scholarworks.csun.edu/bitstream/10211.3/172064/1/mullan-etal-comparative-2006.pdf.
- ↑ "CCDM J10468-4925AB -- Double or multiple star", SIMBAD (Centre de Données astronomiques de Strasbourg), http://simbad.u-strasbg.fr/simbad/sim-id?Ident=HD+93497, retrieved 2012-02-03.
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