Xi² Canis Majoris

Xi² Canis Majoris, which is Latinized from ξ² Canis Majoris, is an astrometric binary[4] star system in the southern constellation of Canis Major. With an apparent visual magnitude of +4.54,[2] it is visible to the naked eye. Based upon an annual parallax shift of 8.35 mas,[1] the system is approximately 390 light years distant from Earth. It is receding with a radial velocity of +26 km/s.[6]

For other stars with this Bayer designation, see ξ Canis Majoris.

Xi² Canis Majoris

Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Canis Major
Right ascension	06^h 35^m 03.38859^s[1]
Declination	−22° 57′ 53.2913″[1]
Apparent magnitude (V)	+4.54[2]
Characteristics
Spectral type	A0 V[3][4] or A0 III[5]
U−B color index	−0.01[2]
B−V color index	−0.06[2]
Astrometry
Radial velocity (Rv)	+26.0±4.2[6] km/s
Proper motion (μ)	RA: +15.437[1] mas/yr Dec.: +18.682[1] mas/yr
Parallax (π)	8.3465 ± 0.2721[1] mas
Distance	390 ± 10 ly (120 ± 4 pc)
Absolute magnitude (MV)	+0.94[7]
Details
Radius	2.7[8] R☉
Luminosity	224[9] L☉
Temperature	8,799[9] K
Rotational velocity (v sin i)	145[10] km/s
Age	339[7] Myr
Other designations
ξ^2 CMa, 5 Canis Majoris, BD−22°1458, FK5 249, GC 8577, HD 46933, HIP 31416, HR 2414, SAO 171982[11]
Database references
SIMBAD	data

The binary nature of this system was determined based on changes in the proper motion of the visible component.[12] Buscombe (1962) gave the white-hued primary a stellar classification of A0 V,[3] indicating it is an A-type main-sequence star. However, Houk and Smith-Moore (1978) list it with a class of A0 III,[5] which would match a more evolved giant star, also of the A-type. It is 339[7] million years old with a high rate of spin, having a projected rotational velocity of 145 km/s.[10] The star is radiating 224[9] times the Sun's luminosity from its photosphere at an effective temperature of 8,799 K.[9]

References

1. Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
2. Johnson, H. L.; et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory, 4 (99), Bibcode:1966CoLPL...4...99J.
3. Buscombe, W. (1962), "Spectral classification of Southern fundamental stars", Mount Stromlo Observatory Mimeogram, 4, Bibcode:1962MtSOM...4....1B.
4. 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.
5. Houk, Nancy; Smith-Moore, M. (1978), Michigan catalogue of two-dimensional spectral types for the HD stars, 4, Ann Arbor: Dept. of Astronomy, University of Michigan, Bibcode:1988mcts.book.....H.
6. 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, A61.
7. Gontcharov, G. A. (November 2012), "Spatial distribution and kinematics of OB stars", Astronomy Letters, 38 (11): 694–706, arXiv:1606.09028, Bibcode:2012AstL...38..694G, doi:10.1134/S1063773712110035.
8. Pasinetti Fracassini, L. E.; Pastori, L.; Covino, S.; Pozzi, A. (2001), "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS)", Astronomy & Astrophysics (3rd ed.), 367: 521–24, arXiv:astro-ph/0012289, Bibcode:2001A&A...367..521P, doi:10.1051/0004-6361:20000451.
9. McDonald, I.; et al. (2012), "Fundamental Parameters and Infrared Excesses of Hipparcos Stars", Monthly Notices of the Royal Astronomical Society, 427 (1): 343–57, arXiv:1208.2037, Bibcode:2012MNRAS.427..343M, doi:10.1111/j.1365-2966.2012.21873.x.
10. Belle, G. T. (2012), "Interferometric observations of rapidly rotating stars", The Astronomy and Astrophysics Review, 20: 51, arXiv:1204.2572, Bibcode:2012A&ARv..20...51V, doi:10.1007/s00159-012-0051-2.
11. "xi02 CMa". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-09-05.
12. Makarov, V. V.; Kaplan, G. H. (May 2005), "Statistical Constraints for Astrometric Binaries with Nonlinear Motion", The Astronomical Journal, 129 (5): 2420–2427, Bibcode:2005AJ....129.2420M, doi:10.1086/429590.