Summary
46 Capricorni is a solitary[8] star located around 790 light years away from the Sun in the southern constellation of Capricornus, near the northern border with Aquarius. It is visible to the naked eye as a dim, yellow-hued point of light with an apparent visual magnitude of +5.10.[2] 46 Cap is also known by its Bayer designation of c Capricorni (c Cap), and occasionally as c1 Capricorni to distinguish it from the nearby star c2 Capricorni.[9] It is moving closer to the Earth with a heliocentric radial velocity of −15.5 km/s.[3]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Capricornus |
| Right ascension | 21h 45m 00.25455s[1] |
| Declination | −09° 04′ 56.7478″[1] |
| Apparent magnitude (V) | 5.10[2] |
| Characteristics | |
| Spectral type | G8Iab[3] or G7.5II-IIICN0.5[4] |
| B−V color index | 1.108±0.001[2] |
| Astrometry | |
| Radial velocity (Rv) | −15.52±0.15[3] km/s |
| Proper motion (μ) | RA: +12.80[5] mas/yr Dec.: −1.31[5] mas/yr |
| Parallax (π) | 4.1489 ± 0.1673 mas[1] |
| Distance | 790 ± 30 ly (241 ± 10 pc) |
| Absolute magnitude (MV) | −1.81[2] |
| Details | |
| Mass | 4.64±0.53[6] M☉ |
| Radius | 32.6±2.3[3] R☉ |
| Luminosity (bolometric) | 627[6] L☉ |
| Surface gravity (log g) | 2.00[3] cgs |
| Temperature | 4,837±18[3] K |
| Metallicity [Fe/H] | +0.01[3] dex |
| Other designations | |
| Database references | |
| SIMBAD | data |
This star has received a stellar classification of G8Iab,[3] which suggests it is a G-type supergiant star, as well as G7.5II-IIICN0.5,[4] which instead indicates a luminosity class between a giant and a bright giant. Abundance analysis suggests the star has not yet passed the first dredge-up.[3] It has 4.6[6] times the mass of the Sun and has expanded to 33[3] times the Sun's radius. The star is radiating 627[6] times the luminosity of the Sun from its photosphere at an effective temperature of 4,837 K.[3]
Etymology edit
This star, along with β Aqr (Sadalsuud) and ξ Aqr (Bunda), were Saʽd al Suʽud (سعد السعود), the Luck of Lucks.[10][11]
References edit
- ^ 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 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 d e f g h i j k Usenko, I. A.; et al. (November 2015). "Spectroscopic studies of four southern-hemisphere G-K supergiants: HD 192876 (α1 Cap), HD 194215 (HR 7801), HD 206834 (c Cap), and HD 222574 (104 Aqr)". Astronomy Letters. 41 (11): 660–676. Bibcode:2015AstL...41..660U. doi:10.1134/S1063773715110067. S2CID 124555577.
- ^ a b Keenan, Philip C.; McNeil, Raymond C. (1989). "The Perkins catalog of revised MK types for the cooler stars". Astrophysical Journal Supplement Series. 71: 245. Bibcode:1989ApJS...71..245K. doi:10.1086/191373.
- ^ 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 c d Hohle, M. M.; et al. (2010). "Masses and luminosities of O- and B-type stars and red supergiants". Astronomische Nachrichten. 331 (4): 349. arXiv:1003.2335. Bibcode:2010AN....331..349H. doi:10.1002/asna.200911355. S2CID 111387483.
- ^ "c Cap". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2014-05-12.
- ^ 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, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976.
- ^ HD 206834, HD-DM-GC-HR-HIP-Bayer-Flamsteed Cross Index, N. D. Kostjuk, Institute of Astronomy of Russian Academy of Sciences, 2002; CDS ID IV/27A.
- ^ Allen, R. H. (1963). Star Names: Their Lore and Meaning (Reprint ed.). New York: Dover Publications Inc. p. 52. ISBN 0-486-21079-0. Retrieved 2010-12-12.
- ^ β Aqr as Nir Saad al Saaoud or Lucida Fortunæ Fortunarum (the brightest of luck of lucks) and ξ Aqr as Thanih Saad al Saaoud or Secunda Fortunæ Fortunarum (the second of luck of lucks). c Cap should be Thalath Fortunæ Fortunarum or Tertia Fortunæ Fortunarum (the third of luck of lucks) consistently, but Al Achsasi Al Mouakket was not designated the title for this star with uncleared consideration. Possibly according to the differences of opinion with R. H. Allen.[citation needed]