Location of ξ Canis Majoris (circled) | |
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Canis Major |
| Right ascension | 06 31 51.36636 |
| Declination | −23° 25′ 06.3181″ |
| Apparent magnitude (V) | 4.33 – 4.36 |
| Characteristics | |
| Spectral type | B1 III |
| U−B color index | −0.98 |
| B−V color index | −0.24 |
| Variable type | β Cep |
| Astrometry | |
| Radial velocity (Rv) | +26.9 km/s |
| Proper motion (μ) | RA: −2.91 mas/yr Dec.: +6.22 mas/yr |
| Parallax (π) | 2.36 ± 0.20 mas |
| Distance | 1,400 ± 100 ly (420 ± 40 pc) |
| Absolute magnitude (MV) | −3.86 |
| Details | |
| Mass | 14.2±0.4 M☉ |
| Radius | 7.9±0.6 R☉ |
| Luminosity | 30,900+8,900 −6,900 L☉ |
| Surface gravity (log g) | 3.78±0.07 cgs |
| Temperature | 27,000±1,000 K |
| Metallicity | −0.18 dex |
| Rotational velocity (v sin i) | 0 km/s |
| Age | 11.1±0.7 Myr |
| Other designations | |
| ξ CMa, 4 Canis Majoris, CD−23°3991, GC 8496, HD 46328, HIP 31125, HR 2387, SAO 171895, ADS 5176, CCDM 06319-2325 | |
| Database references | |
| SIMBAD | data |
Xi Canis Majoris, Latinized from ξ Canis Majoris, is a Beta Cephei variable star in the constellation Canis Major. It is approximately 1,400 light years from Earth.
ξ Canis Majoris is a blue-white B-type star. It has generally been assigned a luminosity class of III (giant) or IV (subgiant), for example B1III or B0.5IV. Comparison of its properties with model evolutionary tracks suggest that it is a main sequence star about three quarters of the way through its main sequence lifetime.
The apparent magnitude varies from +4.33 to +4.36 with a period of 5.03 hours. Its pulsations cause its radius to vary by 1.0% to 1.5%. At the same time its effective temperature by about 500 K above and below its mean temperature.
ξ Canis Majoris has the longest known rotation period of any B class star, taking around 30 years to complete one revolution on its axis. This is thought to be due to magnetic braking; ξ Canis Majoris has the strongest magnetic field of any β Cephei star and would be expected to spin down completely in around four million years. It also has the strongest and hardest X-ray emission of any β Cephei star.
ξ Canis Majoris forms a naked eye pairing with ξ Canis Majoris a little less than a degree away. The Washington Double Star Catalog lists two 14th magnitude companions about 27″ away. In addition, an unseen close companion is suspected due to some faint emission lines in the spectrum that are best explained by a Be star invisible against the brighter primary.
References
- ^ van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. S2CID 18759600.
- ^ "International Variable Star Index". Retrieved 2018-11-13.
- ^ Hubrig, S.; et al. (January 2009). "New magnetic field measurements of beta Cephei stars and Slowly Pulsating B stars". Astronomische Nachrichten. 330 (4): 317. arXiv:0902.1314. Bibcode:2009AN....330..317H. doi:10.1002/asna.200811187. S2CID 17497112.
- ^ 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.
- Evans, D. S. (June 20–24, 1966). "The Revision of the General Catalogue of Radial Velocities". In Batten, Alan Henry; Heard, John Frederick (eds.). Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30. Determination of Radial Velocities and Their Applications. Vol. 30. p. 57. Bibcode:1967IAUS...30...57E.
- ^ Shultz, M.; Wade, G. A.; Rivinius, Th.; Neiner, C.; Henrichs, H.; Marcolino, W.; MiMeS Collaboration (2017). "The pulsating magnetosphere of the extremely slowly rotating magnetic β Cep star ξ CMa". Monthly Notices of the Royal Astronomical Society. 471 (2): 2286. arXiv:1706.08820. Bibcode:2017MNRAS.471.2286S. doi:10.1093/mnras/stx1632.
- Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. S2CID 119257644.
- "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 20 August 2022.
- Shultz, M.; Kochukhov, O.; Wade, G. A.; Rivinius, Th (2018). "The pulsationally modulated radial crossover signature of the slowly rotating magnetic B-type star ξ CMa". Monthly Notices of the Royal Astronomical Society. 478 (1): L39. arXiv:1804.07535. Bibcode:2018MNRAS.478L..39S. doi:10.1093/mnrasl/sly070.
- Mason, Brian D.; Wycoff, Gary L.; Hartkopf, William I.; Douglass, Geoffrey G.; Worley, Charles E. (2001). "The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog". The Astronomical Journal. 122 (6): 3466. Bibcode:2001AJ....122.3466M. doi:10.1086/323920.
| Constellation of Canis Major | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Stars |
| ||||||||||||
| |||||||||||||
| Star clusters |
| ||||||||||||
| |||||||||||||
| Galaxies |
| ||||||||||||
| |||||||||||||
 Category | |||||||||||||