Mu Velorum

μ Velorum
Location of μ Velorum (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Vela
Right ascension 10h 46m 46.17877s[1]
Declination –49° 25′ 12.9244″[1]
Apparent magnitude (V) 2.69[2] (2.7 + 6.4)[3]
Characteristics
Spectral type G5III + G2V[3]
U−B color index +0.57[2]
B−V color index +0.90[2]
Astrometry
Radial velocity (Rv)+6.2[4] km/s
Proper motion (μ) RA: +63.22[1] mas/yr
Dec.: –54.21[1] mas/yr
Parallax (π)29.0506 ± 0.2991 mas[5]
Distance112 ± 1 ly
(34.4 ± 0.4 pc)
Absolute magnitude (MV)−0.06[6]
Orbit[7]
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
Mass3.30[8] M☉
Radius13[9] R☉
Luminosity107[3] L☉
Surface gravity (log g)2.75[8] cgs
Temperature5,047[8] K
Rotational velocity (v sin i)6.4[8] km/s
Age360[3] Myr
Other designations
CD−48°5913, HD 93497, HIP 52727, HR 4216, SAO 222321.[10]
Database references
SIMBADdata

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.[11] (Wulff-Dieter Heintz (1986) lists a period of 138 years with his orbital elements.)[7] 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 estimated to be 117 light-years (36 parsecs).[1] 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[9] times the Sun's radius. The mass of this star is 3.3[8] 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 × 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]

  1. ^ a b c d e Cite error: The named reference aaa474_2_653 was invoked but never defined (see the help page).
  2. ^ a b c d Cite error: The named reference clpl4_99 was invoked but never defined (see the help page).
  3. ^ a b c d e f g h i j Cite error: The named reference apj526_1_445 was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference rgcrv was invoked but never defined (see the help page).
  5. ^ 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.
  6. ^ Cite error: The named reference Cardini2005 was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference aass64_1_1 was invoked but never defined (see the help page).
  8. ^ a b c d e Cite error: The named reference aaa409_251 was invoked but never defined (see the help page).
  9. ^ a b Cite error: The named reference apjss164_1_173 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference bsc1987 was invoked but never defined (see the help page).