Astronomy:Xi2 Canis Majoris
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| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Canis Major |
| Right ascension | 06h 35m 03.388s[1] |
| Declination | −22° 57′ 53.26″[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) | +22.11±0.60[1] km/s |
| Proper motion (μ) | RA: +16.316[1] mas/yr Dec.: +16.885[1] mas/yr |
| Parallax (π) | 8.0342 ± 0.2216[1] mas |
| Distance | 410 ± 10 ly (124 ± 3 pc) |
| Absolute magnitude (MV) | +0.94[6] |
| Details | |
| Mass | 4.08±0.20[7] M☉ |
| Radius | 5.959[8] R☉ |
| Luminosity | 247[8] L☉ |
| Temperature | 9,381[8] K |
| Rotational velocity (v sin i) | 145[9] km/s |
| Age | 339[6] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
Xi2 Canis Majoris is an astrometric binary[4] star system in the southern constellation of Canis Major. Its name is Latinized from ξ2 Canis Majoris, and abbreviated Xi2 CMa or ξ2 CMa. With an apparent visual magnitude of +4.54,[2] it is bright enough to be visible to the naked eye. Based upon an annual parallax shift of 8.03 mas,[1] the system is approximately 410 light years distant from Earth. It is receding with a radial velocity of +22 km/s.[1]
The binary nature of this system was determined based on changes in the proper motion of the visible component.[11] W. Buscombe (1962) gave the white-hued primary a stellar classification of A0 V,[3] indicating it is an A-type main-sequence star. However, N. Houk and M. 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[6] million years old with a high rate of spin, having a projected rotational velocity of 145 km/s. This is giving the star an equatorial bulge that is about 12% wider than the polar diameter.[9] The star has four[7] times the mass of the Sun and six times the Sun's girth. It is radiating 247 times the Sun's luminosity from its photosphere at an effective temperature of 9,381 K.[8]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940. Gaia DR3 record for this source at VizieR.
- ↑ 2.0 2.1 2.2 2.3 Johnson, H. L. et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory 4 (99): 99, Bibcode: 1966CoLPL...4...99J.
- ↑ 3.0 3.1 Buscombe, W. (1962), "Spectral classification of Southern fundamental stars", Mount Stromlo Observatory Mimeogram 4: 1, Bibcode: 1962MtSOM...4....1B.
- ↑ 4.0 4.1 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, doi:10.1111/j.1365-2966.2008.13596.x, Bibcode: 2008MNRAS.389..869E.
- ↑ 5.0 5.1 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.
- ↑ 6.0 6.1 6.2 Gontcharov, G. A. (November 2012), "Spatial distribution and kinematics of OB stars", Astronomy Letters 38 (11): 694–706, doi:10.1134/S1063773712110035, Bibcode: 2012AstL...38..694G.
- ↑ 7.0 7.1 Kervella, Pierre et al. (2019), "Stellar and substellar companions of nearby stars from Gaia DR2: Binarity from proper motion anomaly", Astronomy & Astrophysics 623: A72, doi:10.1051/0004-6361/201834371, ISSN 0004-6361, Bibcode: 2019A&A...623A..72K.
- ↑ 8.0 8.1 8.2 8.3 McDonald, I. et al. (October 2017), "Fundamental parameters and infrared excesses of Tycho-Gaia stars", Monthly Notices of the Royal Astronomical Society 471: 770–791, doi:10.1093/mnras/stx1433, ISSN 0035-8711, Bibcode: 2017MNRAS.471..770M. Xi2 Canis Majoris' database entry at VizieR.
- ↑ 9.0 9.1 Belle, G. T. (2012), "Interferometric observations of rapidly rotating stars", The Astronomy and Astrophysics Review 20 (1): 51, doi:10.1007/s00159-012-0051-2, Bibcode: 2012A&ARv..20...51V.
- ↑ "xi02 CMa". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=xi02+CMa.
- ↑ Makarov, V. V.; Kaplan, G. H. (May 2005), "Statistical Constraints for Astrometric Binaries with Nonlinear Motion", The Astronomical Journal 129 (5): 2420–2427, doi:10.1086/429590, Bibcode: 2005AJ....129.2420M.
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