12 Canis Majoris
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Canis Major |
| Right ascension | 06h 47m 01.48373s[1] |
| Declination | −21° 00′ 55.4494″[1] |
| Apparent magnitude (V) | +6.07[2] |
| Characteristics | |
| Spectral type | B7 II/III[3] or B5 V[4] |
| B−V color index | −0.159±0.004[2] |
| Variable type | SX Ari[5] |
| Astrometry | |
| Radial velocity (Rv) | +16.4±2.5[2] km/s |
| Proper motion (μ) | RA: −14.53[6] mas/yr Dec.: +5.12[6] mas/yr |
| Parallax (π) | 4.3273 ± 0.0824 mas |
| Distance | 750 ± 10 ly (231 ± 4 pc) |
| Absolute magnitude (MV) | −0.81[2] |
| Details | |
| Mass | 1.25[7] M☉ |
| Radius | 2.73[8] R☉ |
| Luminosity | 497.88[2] L☉ |
| Surface gravity (log g) | 4.23[4] cgs |
| Temperature | 15,830±60[9] K |
| Metallicity [Fe/H] | −0.37[10] dex |
| Rotation | 2.18045 d[5] |
| Rotational velocity (v sin i) | 9.5±0.3 km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
12 Canis Majoris is a variable star located 750 light years away from the Sun[1] in the southern constellation of Canis Major.[11] 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.[2] It is moving away from the Earth with a heliocentric radial velocity of +16 km/s.[2] This is the brightest star in the vicinity of the open cluster NGC 2287,[12] although it is probably not a member based on its proper motion.[13]
This star has a stellar classification of B7 II/III,[3] matching a B-type giant/bright giant hybrid.[3] (Cidale et al. (2007) show a class of B5 V,[4] which would indicate it is instead a B-type main-sequence star.) It is a magnetic Bp star[14] of the helium–weak variety (CP4), with the spectrum displaying evidence for vertical stratification of helium in the atmosphere.[15] 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.[5] It has 1.25[7] times the mass of the Sun and 2.73[8] times the Sun's radius. The star is radiating 498[2] times the Sun's luminosity from its photosphere at an effective temperature of 6,500 K.[10]
References
- ^ a b c 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.
- ^ a b c d e f g h 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 c 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 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.
- ^ a b Goupil, M. J.; et al. (November 2006), "Rotational Splittings with CoRoT, Expected Number of Detections and Measurement Accuracy", in Fridlund, M.; Baglin, A.; Lochard, J.; Conroy, L. (eds.), Proceedings of "The CoRoT Mission Pre-Launch Status - Stellar Seismology and Planet Finding" (ESA SP-1306), vol. 1306, p. 453, Bibcode:2006ESASP1306..453G, ISBN 92-9092-465-9.
- ^ 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.
{{citation}}: CS1 maint: unflagged free DOI (link) - ^ 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.
- ^ a b Mosser, B.; et al. (February 2005), "Seismology and activity of the F type star HD 49933", Astronomy and Astrophysics, 431: L13–L16, arXiv:astro-ph/0501459, Bibcode:2005A&A...431L..13M, doi:10.1051/0004-6361:200500003, S2CID 18412104.
- ^ 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.
