Mu Canis Majoris

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Mu Canis Majoris
Canis Major constellation map.svg
Red circle.svg
Location of μ Canis Majoris (circled)
Observation data
Epoch J2000.0        Equinox J2000.0 (ICRS)
Constellation Canis Major
μ CMa A
Right ascension 06h 56m 06.6459s [1]
Declination −14° 02′ 36.351″ [1]
Apparent magnitude  (V)5.27 [2]
μ CMa B
Right ascension 06h 56m 06.5891s [3]
Declination −14° 02′ 33.633″ [3]
Apparent magnitude  (V)7.32 [2]
Characteristics
Spectral type K2/3 III + B9/A0 V [4]
Astrometry
μ CMa A
Radial velocity (Rv)18.1±0.1 [5] km/s
Proper motion (μ)RA: −1.106 mas/yr [1]
Dec.: +6.383 mas/yr [1]
Parallax (π)3.4219±0.0937  mas [1]
Distance 950 ± 30  ly
(292 ± 8  pc)
Absolute magnitude  (MV)−2.22 [6]
μ CMa B
Proper motion (μ)RA: +0.355 mas/yr [3]
Dec.: +6.594 mas/yr [3]
Parallax (π)3.4079±0.0551  mas [3]
Distance 960 ± 20  ly
(293 ± 5  pc)
Orbit [7]
PrimaryA
CompanionB
Semi-major axis (a)829  AU
Eccentricity (e)0.62+0.29
−0.23
Details
μ CMa A
Mass 5.4 [1]   M☉
Radius 80 [1]   R☉
Luminosity 1,660 [1]   L☉
Surface gravity (log g)1.14 [8]   cgs
Temperature 4,123 [8]   K
Rotational velocity (v sin i)≤ 5 [9]  km/s
Age 100 [8]   Myr
μ CMa B
Mass 1.6 [10]   M☉
Surface gravity (log g)2.70 [10]   cgs
Temperature 5,034 [10]   K
Other designations
μ CMa, 18 Canis Majoris, BD−13°1741, HIP 33345, HR 2593, SAO 152123 [11]
μ CMa A: HD 51250 [11]
μ CMa B: HD 51251 [12]
Database references
SIMBAD A
B

Mu Canis Majoris is a binary star [2] 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, [13] and the components can be split with a small telescope. [14] 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. [2] Based upon an annual parallax shift of 3.42  mas as seen from Earth, [1] 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. [15]

As of 2011, the pair had an angular separation of 2.77  arc seconds along a position angle of 343.9°. [16] The orange-hued primary member, component A, is an evolved K-type giant star with a stellar classification of K2/3 III [4] and a visual magnitude of 5.27. [2] It has 5.4 times the mass, 80 times the radius, and 1,660 times the luminosity of the Sun. [1] The base magnitude 7.32 [2] companion, component B, is a hybrid B/A-type main-sequence star with a class of B9/A0 V. [4] It has 1.6 times the mass of the Sun and is the hotter star, having an effective temperature of 5,034 K, [10] compared to 4,123 K for the primary. [8]

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″. [17] Mu CMa should not be confused with the 9th magnitude variable star MU CMa located near NGC 2360. [18]

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.
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