Nu3 Canis Majoris

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Nu3 Canis Majoris
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Canis Major
Right ascension 06h 37m 53.42144s[1]
Declination −18° 14′ 14.9218″[1]
Apparent magnitude (V) 4.41[2] (4.63 + 8.56)[3]
Spectral type K0 II-III[4]
U−B color index +1.04[2]
B−V color index +1.16[2]
Radial velocity (Rv)−1.50±0.70[5] km/s
Proper motion (μ) RA: −7.32[1] mas/yr
Dec.: −8.72[1] mas/yr
Parallax (π)7.74 ± 0.43[1] mas
Distance420 ± 20 ly
(129 ± 7 pc)
Absolute magnitude (MV)−1.13[6]
ν3 CMa A
Mass3.38±0.37[7] M
Radius32.7 R
Luminosity398 L
Surface gravity (log g)2.34 cgs
Temperature4,510 K
Metallicity [Fe/H]−0.24 dex
Rotation183 d
Rotational velocity (v sin i)8[8] km/s
Age380±20[7] Myr
Other designations
ν3 CMa, 8 CMa, BD−18° 1492, GC 8660, HD 47442, HIP 31700, HR 2443, SAO 151730, CCDM 06379-1814[9]
Database references

Nu3 Canis Majoris, Latinized from ν3 Canis Majoris, is a binary star[3] system in the southern constellation of Canis Major. It is visible to the naked eye with a combined apparent visual magnitude of 4.41.[2] Based upon an annual parallax shift of 7.74 mas as seen from Earth,[1] this system is located about 420 light years from the Sun.

The primary member, component A, is an evolved, orange-hued giant/bright giant hybrid with an apparent magnitude of +4.63[3] and a stellar classification of K0 II-III.[4] It is most likely (96% chance) on the horizontal branch.[7] The star has a moderate level of surface activity with a magnetic field strength of 2.2±0.4 G and is a source of X-ray emission with a luminosity of 624×1027 erg s−1.[4]

This giant has an estimated 3.4[7] times the mass of the Sun and has expanded to 33[4] times the Sun's radius. It is radiating 398 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,510 K.[4] The star is spinning with the leisurely period of 183 days.[4] Its companion, component B, is 1.040 arcseconds distant and has an apparent magnitude of +8.56.[3]


  1. ^ a b c d e f van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752Freely accessible, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357. 
  2. ^ a b c d Fernie, J. D. (May 1983), "New UBVRI photometry for 900 supergiants", Astrophysical Journal Supplement Series, 52: 7–22, Bibcode:1983ApJS...52....7F, doi:10.1086/190856. 
  3. ^ a b c d Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878Freely accessible, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x. 
  4. ^ a b c d e f g Aurière, M.; et al. (2015), "The magnetic fields at the surface of active single G-K giants", Astronomy & Astrophysics, 574, arXiv:1411.6230Freely accessible, Bibcode:2015A&A...574A..90A, doi:10.1051/0004-6361/201424579, A90. 
  5. ^ de Bruijne, J. H. J.; Eilers, A.-C. (October 2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", Astronomy & Astrophysics, 546: 14, arXiv:1208.3048Freely accessible, Bibcode:2012A&A...546A..61D, doi:10.1051/0004-6361/201219219, A61. 
  6. ^ Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971Freely accessible, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015. 
  7. ^ a b c d Reffert, Sabine; et al. (2015), "Precise radial velocities of giant stars. VII. Occurrence rate of giant extrasolar planets as a function of mass and metallicity", Astronomy & Astrophysics, 574: A116, arXiv:1412.4634Freely accessible, Bibcode:2015A&A...574A.116R, doi:10.1051/0004-6361/201322360. 
  8. ^ Bernacca, P. L.; Perinotto, M. (1970), "A catalogue of stellar rotational velocities", Contributi Osservatorio Astronomico di Padova in Asiago, 239 (1), Bibcode:1970CoAsi.239....1B. 
  9. ^ "nu03 CMa". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-09-05.