Variable star in the constellation Canis Major
12 Canis Majoris ![](//upload.wikimedia.org/wikipedia/commons/thumb/3/3f/HKCMaLightCurve.png/250px-HKCMaLightCurve.png) A visual band light curve for HK Canis Majoris (2020) [1] |
Observation data Epoch J2000 Equinox J2000 |
Constellation | Canis Major |
Right ascension | 06h 47m 01.48353s[2] |
Declination | −21° 00′ 55.4517″[2] |
Apparent magnitude (V) | +6.07[3] |
Characteristics |
Spectral type | B7 II/III[4] or B5 V[5] |
B−V color index | −0.159±0.004[3] |
Variable type | SX Ari[6] |
Astrometry |
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Radial velocity (Rv) | +16.4±2.5[3] km/s |
Proper motion (μ) | RA: −14.568[2] mas/yr Dec.: +5.778[2] mas/yr |
Parallax (π) | 4.6155 ± 0.0543 mas |
Distance | 707 ± 8 ly (217 ± 3 pc) |
Absolute magnitude (MV) | −0.81[3] |
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Details |
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Mass | 4.8[7] M☉ |
Radius | 2.73[8] R☉ |
Luminosity | 537[9] L☉ |
Surface gravity (log g) | 4.23[5] cgs |
Temperature | 15,830±60[9] K |
Metallicity [Fe/H] | −0.37[10] dex |
Rotation | 2.18045 d[7] |
Rotational velocity (v sin i) | 65[7] km/s |
Age | 134[11] Myr |
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Other designations |
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Database references |
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SIMBAD | data |
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] 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
- ^ 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.
- ^ 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.
- ^ 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.
- ^ 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.
- ^ 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.
- ^ 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.
- ^ 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.
- ^ 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.
- ^ 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.
- ^ 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.
- ^ 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.
- ^ a b "12 CMa". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved April 30, 2019.
- ^ 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.
- ^ Levato, H.; Garcia, B. (1984), "Axial rotation in NGC 2287", Astrophysical Letters, 24 (3): 161–164, Bibcode:1984ApL....24..161L.
- ^ 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.
- ^ 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.