KNOWPIA
WELCOME TO KNOWPIA
Zeta Cephei 
Summary
Zeta Cephei (ζ Cep, ζ Cephei) is a star in the constellation of Cepheus. Zeta Cephei marks the left shoulder of Cepheus, the King of Joppa (Ethiopia).[clarification needed] It is one of the fundamental stars of the MK spectral sequence, defined as type K1.5 Ib.
  | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Cepheus |
| Right ascension | 22h 10m 51.279s[1] |
| Declination | +58° 12′ 04.53″[1] |
| Apparent magnitude (V) | 3.35[2] |
| Characteristics | |
| Spectral type | K1.5 Ib[3] |
| B−V color index | +1.55[2] |
| Variable type | Eclipsing binary?[4] |
| Astrometry | |
| Proper motion (μ) | RA: 12.654 ± 0.4618[1] mas/yr Dec.: 5.989 ± 0.835[1] mas/yr |
| Parallax (π) | 3.2972 ± 0.1456 mas[5] |
| Distance | 990 ± 40 ly (300 ± 10 pc) |
| Absolute magnitude (MV) | −4.7[6] |
| Details | |
| Radius | 172.7+7.5 −8.3[7] R☉ |
| Luminosity | 10,024±1,052[7] L☉ |
| Surface gravity (log g) | 0.75[8] cgs |
| Temperature | 4,393±58[7] K |
| Metallicity [Fe/H] | +0.04[7] dex |
| Rotational velocity (v sin i) | 10.64[9] km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
Zeta Cephei is a red supergiant star with a surface temperature of 4,393 K and a radius of 172 R☉.[7] The luminosity of Zeta Cephei is approximately 10,000 times that of the Sun.[7] At a distance of about 840 light-years,[10] Zeta Cephei has an apparent magnitude (m) of 3.4 and an absolute magnitude (M) of -4.7. The star has a metallicity approximately 1.6 times that of the Sun; i.e., it contains 1.6 times as much heavy-element material as the Sun.
Hekker et al. (2008) have detected a periodicity of 533 days, hinting at the possible presence of an as yet unseen companion.[11] It is listed as a possible eclipsing binary with a very small amplitude.[4]
References edit
- ^ a b c d 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 Levesque, Emily M.; Massey, Philip; Olsen, K. A. G.; Plez, Bertrand; Josselin, Eric; Maeder, Andre; Meynet, Georges (2005). "The Effective Temperature Scale of Galactic Red Supergiants: Cool, but Not As Cool As We Thought". The Astrophysical Journal. 628 (2): 973–985. arXiv:astro-ph/0504337. Bibcode:2005ApJ...628..973L. doi:10.1086/430901. S2CID 15109583.
- ^ Morgan, W. W.; Keenan, P. C. (1973). "Spectral Classification". Annual Review of Astronomy and Astrophysics. 11: 29–50. Bibcode:1973ARA&A..11...29M. doi:10.1146/annurev.aa.11.090173.000333.
- ^ a b Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007–2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S. 1: 02025. Bibcode:2009yCat....102025S.
- ^ Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
- ^ Luck, R. E. (1982). "The chemical composition of late-type supergiants. IV - Homogeneous abundances and galactic metallicity trends". Astrophysical Journal. 256: 177. Bibcode:1982ApJ...256..177L. doi:10.1086/159895.
- ^ a b c d e f Baines, Ellyn K.; Armstrong, J. Thomas; Clark III, James H.; Gorney, Jim; Hutter, Donald J.; Jorgensen, Anders M.; Kyte, Casey; Mozurkewich, David; Nisley, Ishara; Sanborn, Jason; Schmitt, Henrique R.; van Belle, Gerard T. (2021-11-01). "Angular Diameters and Fundamental Parameters of Forty-Four Stars from the Navy Precision Optical Interferometer". The Astronomical Journal. 162 (5): 198. arXiv:2211.09030. Bibcode:2021AJ....162..198B. doi:10.3847/1538-3881/ac2431. ISSN 0004-6256.
- ^ Mallik, Sushma V. (December 1999), "Lithium abundance and mass", Astronomy and Astrophysics, 352: 495–507, Bibcode:1999A&A...352..495M
- ^ Hekker, S.; Meléndez, J. (2007). "Precise radial velocities of giant stars. III. Spectroscopic stellar parameters". Astronomy and Astrophysics. 475 (3): 1003. arXiv:0709.1145. Bibcode:2007A&A...475.1003H. doi:10.1051/0004-6361:20078233. S2CID 10436552.
- ^ 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.Vizier catalog entry
- ^ Hekker; et al. (2008). "Precise radial velocities of giant stars. IV. A correlation between surface gravity and radial velocity variation and a statistical investigation of companion properties". Astronomy and Astrophysics. 480 (1): 215–222. arXiv:0801.0741. Bibcode:2008A&A...480..215H. doi:10.1051/0004-6361:20078321. S2CID 33442610.