12 Canis Majoris is a variable star located about 707 light years away from the Sun in the southern constellation of Canis Major.[12] It has the variable star designation HK Canis Majoris; 12 Canis Majoris is the Flamsteed designation. This body is just barely visible to the naked eye as a dim, blue-white hued star with a baseline apparent visual magnitude of +6.07.[3] It is moving away from the Earth with a heliocentric radial velocity of +16 km/s.[3] This is the brightest star in the vicinity of the open cluster NGC 2287,[13] although it is probably not a member based on its proper motion.[14]

This star has a stellar classification of B7 II/III,[4] matching the spectrum of a B-type star intermediate between a giant and bright giant.[4] (Cidale et al. (2007) show a class of B5 V,[5] which would indicate it is instead a B-type main-sequence star.) It is a magnetic Bp star[15] of the helium–weak variety (CP4), with the spectrum displaying evidence for vertical stratification of helium in the atmosphere.[16]

Holger Pedersen and Bjarne Thomsen discovered that 12 Canis Majoris is a variable star, in 1977.[17] It was given its variable star designation in 1981.[18] Samus et al. (2017) classify it as an SX Arietis variable that varies in brightness by about 0.05 magnitudes over a period of 2.18045 days.[6] It has 4.8 times the mass of the Sun and 2.73[8] times the Sun's radius. The star is radiating 537 times the Sun's luminosity from its photosphere at an effective temperature of 15,830 K.

References

  1. ^ Bernhard, Klaus; Hũmmerich, Stefan; Paunzen, Ernst (17 February 2020). "New and improved rotational periods of magnetic CP stars from ASAS-3, KELT, and MASCARA data". Monthly Notices of the Royal Astronomical Society. 493 (3): 3293–3330. arXiv:2002.06435. Bibcode:2020MNRAS.493.3293B. doi:10.1093/mnras/staa462.
  2. ^ a b c d 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.
  3. ^ a b c d e f 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.
  4. ^ a b c 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. ^ a b c Cidale, L. S.; et al. (June 2007), "Fundamental parameters of He-weak and He-strong stars", Astronomy and Astrophysics, 468 (1): 263–272, arXiv:0705.0541, Bibcode:2007A&A...468..263C, doi:10.1051/0004-6361:20066454, S2CID 14143604.
  6. ^ a b Samus, N. N.; et al. (2017), "General Catalogue of Variable Stars", Astronomy Reports, 5.1, 61 (1): 80–88, Bibcode:2017ARep...61...80S, doi:10.1134/S1063772917010085, S2CID 125853869.
  7. ^ a b c Shultz, M. E.; Owocki, S. P.; Ud-Doula, A.; Biswas, A.; Bohlender, D.; Chandra, P.; Das, B.; David-Uraz, A.; Khalack, V.; Kochukhov, O.; Landstreet, J. D.; Leto, P.; Monin, D.; Neiner, C.; Rivinius, Th; Wade, G. A. (2022). "MOBSTER - VI. The crucial influence of rotation on the radio magnetospheres of hot stars". Monthly Notices of the Royal Astronomical Society. 513 (1): 1429. arXiv:2201.05512. Bibcode:2022MNRAS.513.1429S. doi:10.1093/mnras/stac136.
  8. ^ a b Shulyak, D.; et al. (2014), "Interferometry of chemically peculiar stars: Theoretical predictions versus modern observing facilities", Monthly Notices of the Royal Astronomical Society, 443 (2): 1629, arXiv:1406.6093, Bibcode:2014MNRAS.443.1629S, doi:10.1093/mnras/stu1259, S2CID 96452769.
  9. ^ a b Netopil, M.; et al. (November 2008), "Chemically peculiar stars and their temperature calibration", Astronomy and Astrophysics, 491 (2): 545–554, arXiv:0809.5131, Bibcode:2008A&A...491..545N, doi:10.1051/0004-6361:200810325, S2CID 14084961.
  10. ^ Mosser, B.; et al. (February 2005), "Seismology and activity of the F type star HD 49933", Astronomy and Astrophysics, 431 (2): L13 – L16, arXiv:astro-ph/0501459, Bibcode:2005A&A...431L..13M, doi:10.1051/0004-6361:200500003, S2CID 18412104.
  11. ^ Gontcharov, G. A. (December 2012). "Dependence of kinematics on the age of stars in the solar neighborhood". Astronomy Letters. 38 (12): 771–782. arXiv:1606.08814. Bibcode:2012AstL...38..771G. doi:10.1134/S1063773712120031. eISSN 1562-6873. ISSN 1063-7737.
  12. ^ a b "12 CMa". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved April 30, 2019.
  13. ^ Feinstein, A.; et al. (1979), "Multicolor photometry of the open cluster NGC 2287", International Astronomical Union, Reunion Astronomica Regional Latinoamericana, 1st, Santiago, Chile, Jan. 16-21, 1978, vol. 3, Chile, Universidad: Departamento de Astronomia, Publicaciones, pp. 146–149, Bibcode:1979rarl.conf..146F.
  14. ^ Levato, H.; Garcia, B. (1984), "Axial rotation in NGC 2287", Astrophysical Letters, 24 (3): 161–164, Bibcode:1984ApL....24..161L.
  15. ^ Bailey, J. D.; Landstreet, J. D. (2013), "Abundances determined using Si ii and Si iii in B-type stars: Evidence for stratification", Astronomy & Astrophysics, 551: A30, arXiv:1301.3050, Bibcode:2013A&A...551A..30B, doi:10.1051/0004-6361/201220671, S2CID 59291051.
  16. ^ Farthmann, M.; et al. (November 1994), "Stratification of helium in the photospheres of the helium-weak stars HD 28843 and HD 49333", Astronomy and Astrophysics, 291: 919–927, Bibcode:1994A&A...291..919F.
  17. ^ Pedersen, H.; Thomsen, B. (October 1977). "Spectrum and photometric variability of He-weak and He-strong stars". Astronomy and Astrophysics, Suppl. Ser. 30: 11–25. Bibcode:1977A&AS...30...11P. Retrieved 1 January 2025.
  18. ^ Kholopov, P. N.; Samus, N. N.; Kukarkina, N. P.; Medvedeva, G. I.; Perova, N. B. (February 1981). "65th Name-List of Variable Stars" (PDF). Information Bulletin on Variable Stars. 1921. Bibcode:1981IBVS.1921....1K. Retrieved 1 January 2025.
Allikas: https://en.wikipedia.org/wiki/12_Canis_Majoris
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