Location of μ Velorum (circled) | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Vela |
| Right ascension | 10 46 46.17877 |
| Declination | –49° 25′ 12.9244″ |
| Apparent magnitude (V) | 2.69 (2.7 + 6.4) |
| Characteristics | |
| Spectral type | G5III + G2V |
| U−B color index | +0.57 |
| B−V color index | +0.90 |
| Astrometry | |
| Radial velocity (Rv) | +6.2 km/s |
| Proper motion (μ) | RA: +63.22 mas/yr Dec.: –54.21 mas/yr |
| Parallax (π) | 29.0506 ± 0.2991 mas |
| Distance | 112 ± 1 ly (34.4 ± 0.4 pc) |
| Absolute magnitude (MV) | −0.06 |
| Orbit | |
| Period (P) | 138 yr |
| Semi-major axis (a) | 1.427″ |
| Eccentricity (e) | 0.84 |
| Inclination (i) | 57.0° |
| Longitude of the node (Ω) | 59.1° |
| Periastron epoch (T) | 1951.1 |
| Argument of periastron (ω) (secondary) | 178.0° |
| Details | |
| μ Vel A | |
| Mass | 3.30 M☉ |
| Radius | 13 R☉ |
| Luminosity | 107 L☉ |
| Surface gravity (log g) | 2.75 cgs |
| Temperature | 5,047 K |
| Rotational velocity (v sin i) | 6.4 km/s |
| Age | 360 Myr |
| Other designations | |
| CD−48°5913, HD 93497, HIP 52727, HR 4216, SAO 222321. | |
| Database references | |
| SIMBAD | data |
Mu Velorum (μ Vel, μ Velorum) is a binary star system in the southern constellation Vela. The two stars orbit each other with a semi-major axis of 1.437 arcseconds and a period of 116.24 years. (Wulff-Dieter Heintz (1986) lists a period of 138 years with his orbital elements.) The pair have a combined apparent visual magnitude of 2.69, making the system readily visible to the naked eye. From parallax measurements, the distance to this system is estimated to be 117 light-years (36 parsecs). The system is about 360 million years old.
The primary component is a giant star with an apparent magnitude of 2.7 and a stellar classification of G5 III. It is radiating about 107 times the luminosity of the Sun from an expanded atmosphere about 13 times the Sun's radius. The mass of this star is 3.3 times that of the Sun. 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 × 10 erg s.
The fainter companion, Mu Velorum B, is a main sequence star with an apparent magnitude of 6.4 and an assigned stellar classification of G2V. 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.
References
- ^ 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.
- ^ 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.
- ^ 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, Bibcode:1999ApJ...526..445A, doi:10.1086/308001, S2CID 120689663.
- Evans, D. S. (June 20–24, 1966), "The Revision of the General Catalogue of Radial Velocities", in Batten, Alan Henry; Heard, John Frederick (eds.), Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30, vol. 30, University of Toronto: International Astronomical Union, p. 57, Bibcode:1967IAUS...30...57E.
- Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
- Cardini, D. (January 2005), "Mg II chromospheric radiative loss rates in cool active and quiet stars", Astronomy and Astrophysics, 430: 303–311, arXiv:astro-ph/0409683, Bibcode:2005A&A...430..303C, doi:10.1051/0004-6361:20041440, S2CID 12136256.
- ^ Heintz, W. D. (April 1986), "Orbits of 20 visual binaries", Astronomy and Astrophysics Supplement Series, 64 (1): 1–7, Bibcode:1986A&AS...64....1H. Listed as Ru 155.
- ^ 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, Bibcode:2003A&A...409..251M, doi:10.1051/0004-6361:20031084.
- ^ Mullan, D. J.; et al. (May 2006), "A Comparative Study of Flaring Loops in Active Stars" (PDF), The Astrophysical Journal Supplement Series, 164 (1): 173–201, Bibcode:2006ApJS..164..173M, doi:10.1086/502629, hdl:10211.3/172064, S2CID 122152694.
- "CCDM J10468-4925AB -- Double or multiple star", SIMBAD, Centre de Données astronomiques de Strasbourg, retrieved 2012-02-03.
- Hoffleit, D.; Warren, W. H. Jr. (1987), "The Bright Star Catalogue", Astronomical Data Center Bulletin, 1 (4) (5th revised ed.): 285–294, Bibcode:1987ADCBu...1..285H.
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