Mu Canis Majoris

Mu Canis Majoris
Location of μ Canis Majoris (circled)
Observation data
Epoch J2000.0      Equinox ICRS
Constellation Canis Major
μ CMa A
Right ascension 06h 56m 06.6459s
Declination −14° 02′ 36.351″
Apparent magnitude (V) 5.27
μ CMa B
Right ascension 06h 56m 06.5891s
Declination −14° 02′ 33.633″
Apparent magnitude (V) 7.32
Characteristics
Spectral type K2/3 III + B9/A0 V
Astrometry
μ CMa A
Radial velocity (Rv)18.1±0.1 km/s
Proper motion (μ) RA: −1.106 mas/yr
Dec.: +6.383 mas/yr
Parallax (π)3.4219±0.0937 mas
Distance950 ± 30 ly
(292 ± 8 pc)
Absolute magnitude (MV)−2.22
μ CMa B
Proper motion (μ) RA: +0.355 mas/yr
Dec.: +6.594 mas/yr
Parallax (π)3.4079±0.0551 mas
Distance960 ± 20 ly
(293 ± 5 pc)
Orbit
PrimaryA
SecondaryB
Semi-major axis (a)829 AU
Eccentricity (e)0.62+0.29
−0.23
Details
μ CMa A
Mass5.4 M☉
Radius80 R☉
Luminosity1,660 L☉
Surface gravity (log g)1.14 cgs
Temperature4,123 K
Rotational velocity (v sin i)≤ 5 km/s
Age100 Myr
μ CMa B
Mass1.6 M☉
Surface gravity (log g)2.70 cgs
Temperature5,034 K
Other designations
μ CMa, 18 Canis Majoris, BD−13°1741, HIP 33345, HR 2593, SAO 152123
μ CMa A: HD 51250
μ CMa B: HD 51251
Database references
SIMBADA
B

Mu Canis Majoris is a binary star system in the southern constellation of Canis Major. The pair can be located a little to the southwest of the point midway between Gamma and Theta Canis Majoris, and the components can be split with a small telescope. Their name is a Bayer designation that is Latinized from μ Canis Majoris, and abbreviated as Mu CMa or μ CMa. The system is faintly visible to the naked eye with a combined apparent visual magnitude of 5.12. Based upon an annual parallax shift of 3.42 mas as seen from Earth, this system is located roughly 950–960 light years from the Sun.

Grotius assigned the name Isis to this star, but the name, now obsolete, belonged rather to Gamma Canis Majoris.

As of 2011, the pair had an angular separation of 2.77 arc seconds along a position angle of 343.9°. The orange-hued primary member, component A, is an evolved K-type giant star with a stellar classification of K2/3 III and a visual magnitude of 5.27. It has 5.4 times the mass, 80 times the radius, and 1,660 times the luminosity of the Sun. The base magnitude 7.32 companion, component B, is a hybrid B/A-type main-sequence star with a class of B9/A0 V. It has 1.6 times the mass of the Sun and is the hotter star, having an effective temperature of 5,034 K, compared to 4,123 K for the primary.

The system has two visual companions. As of 2008, magnitude 10.32 component C lies at an angular separation of 86.90″, while magnitude 10.64 component D is at a separation of 105.0″. Mu CMa should not be confused with the 9th magnitude variable star MU CMa located near NGC 2360.

References

  1. 1 2 3 4 5 6 7 8 9 10 Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  2. 1 2 3 4 5 6 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:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976.
  3. 1 2 3 4 5 Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  4. 1 2 3 Houk, Nancy; Smith-Moore, M. (1978), Michigan catalogue of two-dimensional spectral types for the HD stars, vol. 4, Ann Arbor: Dept. of Astronomy, University of Michigan, Bibcode:1988mcts.book.....H.
  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:1208.3048, Bibcode:2012A&A...546A..61D, doi:10.1051/0004-6361/201219219, S2CID 59451347, A61.
  6. ↑ Ginestet, N.; Carquillat, J. M. (2002), "Spectral Classification of the Hot Components of a Large Sample of Stars with Composite Spectra, and Implication for the Absolute Magnitudes of the Cool Supergiant Components", The Astrophysical Journal Supplement Series, 143 (2): 513, Bibcode:2002ApJS..143..513G, doi:10.1086/342942.
  7. ↑ Hwang, Hsiang-Chih; et al. (May 2022), "The eccentricity distribution of wide binaries and their individual measurements", Monthly Notices of the Royal Astronomical Society, 512 (3): 3383–3399, arXiv:2111.01789, Bibcode:2022MNRAS.512.3383H, doi:10.1093/mnras/stac675, ISSN 0035-8711.
  8. 1 2 3 4 Kordopatis, G.; et al. (2023), "Stellar ages, masses, extinctions, and orbital parameters based on spectroscopic parameters of Gaia DR3", Astronomy and Astrophysics, 669: A104, arXiv:2206.07937, Bibcode:2023A&A...669A.104K, doi:10.1051/0004-6361/202244283.
  9. ↑ Eaton, J. A. (May 1990), "Rotational Velocities of G and K Giants", Information Bulletin on Variable Stars, 3460: 1, Bibcode:1990IBVS.3460....1E.
  10. 1 2 3 4 Anders, F.; et al. (August 2019), "Photo-astrometric distances, extinctions, and astrophysical parameters for Gaia DR2 stars brighter than G = 18", Astronomy and Astrophysics, 628: A94, arXiv:1904.11302, Bibcode:2019A&A...628A..94A, doi:10.1051/0004-6361/201935765, ISSN 0004-6361
  11. 1 2 "mu. CMa", SIMBAD, Centre de données astronomiques de Strasbourg, retrieved 2017-09-07.
  12. ↑ "HD 51251", SIMBAD, Centre de données astronomiques de Strasbourg, retrieved 2017-09-07.
  13. ↑ O'Meara, Steve (2007), Herschel 400 Observing Guide, Cambridge University Press, p. 63, ISBN 978-0521858939.
  14. ↑ Consolmagno, Guy (2011), Turn Left at Orion: Hundreds of Night Sky Objects to See in a Home Telescope – and How to Find Them, Cambridge, United Kingdom: Cambridge University Press, p. 81, ISBN 978-1-139-50373-0.
  15. ↑ Allen, Richard Hinckley (June 1963), Star Names: Their Lore and Meaning, Dover Publications, ISBN 978-0486210797.{{citation}}: CS1 maint: ignored ISBN errors (link)
  16. ↑ Mason, Brian D.; et al. (May 2012), "Speckle Interferometry at the U.S. Naval Observatory. XVIII" (PDF), The Astronomical Journal, 143 (5): 6, Bibcode:2012AJ....143..124M, doi:10.1088/0004-6256/143/5/124, 124, archived from the original on June 13, 2017.
  17. ↑ Mason, B. D.; et al. (2014), "The Washington Visual Double Star Catalog", The Astronomical Journal, 122 (6): 3466, Bibcode:2001AJ....122.3466M, doi:10.1086/323920.
  18. ↑ International variable star Index: MU CMa, AAVSO, retrieved 2012-06-03.