Zeta Cephei
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Cepheus |
| Right ascension | 22h 10m 51.277s[1] |
| Declination | +58° 12′ 04.54″[1] |
| Apparent magnitude (V) | 3.35[2] |
| Characteristics | |
| Evolutionary stage | Red supergiant[3] |
| Spectral type | K1.5 Ib[4] |
| B−V color index | +1.55[2] |
| Astrometry | |
| Proper motion (μ) | RA: 13.359±0.148 mas/yr[1] Dec.: 5.275±0.183 mas/yr[1] |
| Parallax (π) | 3.2972±0.1456 mas[1] |
| Distance | 992.7+51.2 −46 ly (304.5+15.7 −14.1 pc)[5] |
| Absolute magnitude (MV) | −4.7[3] |
| Details | |
| Mass | 10.1±0.1[6] M☉ |
| 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 | |
| 21 Cephei, BD+57°2475, FK5 836, HD 210745, HIP 109492, HR 8465, SAO 34137, Gaia DR2 2199493438511811712, Gaia DR3 2199493438511811712[10] | |
| Database references | |
| SIMBAD | data |
Zeta Cephei is a red supergiant star in the northern constellation of Cepheus. Its name is a Bayer designation that is Latinized from ζ Cephei, and abbreviated Zeta Cep or ζ Cep. With an apparent visual magnitude of 3.35,[2] it is a third-magnitude star that is visible to the naked eye. Based on parallax measurements, it is located about 1000 light-years away from the Earth. Zeta Cephei marks the left shoulder of Cepheus, a mythical King of Aethiopia. It is one of the fundamental stars of the MK spectral sequence, defined as type K1.5 Ib.
Characteristics
Zeta Cephei has a spectral classification of K1.5Ib,[4] indicating that it is a lower luminosity red supergiant star. It is about 173 times larger than the Sun and has a surface temperature of 4,393 K.[7] The luminosity of Zeta Cephei is approximately 10,000 times that of the Sun.[7] At a distance of about 840 light-years,[11] Zeta Cephei has an apparent magnitude (m) of 3.4 and an absolute magnitude (M) of -3.7.[12] The star has a metallicity similar to the Sun.[7]
At a mass of 10.1 M☉, Zeta Cephei might end its life in a core-collapse supernova, and has been listed as a likely pre-supernova candidate by a 2022 study. It could also provide observable pre-supernova neutrino signals, just hours before the core collapses.[6]
Hekker et al. (2008) have detected a periodicity of 533 days, hinting at the possible presence of an as yet unseen companion.[13] It is listed as a candidate eclipsing binary with a very small amplitude.[14] However, spectroscopic measurements made from 1993 to 2015 do not support the presence of the companion.[12]
References
- ^ 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 Ducati, J. R. (2002-01-01). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". VizieR Online Data Catalog. 2237. Bibcode:2002yCat.2237....0D. Zeta Cephei's database entry at VizieR.
- ^ a b 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 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.
- ^ Bailer-Jones, C. A. L.; et al. (2021-03-01). "Estimating distances from parallaxes. V: Geometric and photogeometric distances to 1.47 billion stars in Gaia Early Data Release 3". The Astronomical Journal. 161 (3): 147. arXiv:2012.05220. Bibcode:2021AJ....161..147B. doi:10.3847/1538-3881/abd806. ISSN 0004-6256. Data about this star can be seen here.
- ^ a b Machado, L. N.; et al. (2022-08-12). "Pre-supernova Alert System for Super-Kamiokande". The Astrophysical Journal. 935 (1): 40. arXiv:2205.09881. Bibcode:2022ApJ...935...40M. doi:10.3847/1538-4357/ac7f9c. ISSN 0004-637X.
- ^ a b c d e f g Baines, Ellyn K.; et al. (November 2021). "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.
- ^ "zet Cep". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2026-01-19.
- ^ 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 Archived 2016-03-04 at the Wayback Machine
- ^ a b R. F., Griffin (April 2015). "Spectroscopic binary orbits from photoelectric radial velocities. Paper 241: HR 1884, HD 174103, HD 182563, and HR 8442, with a note on zeta Cephei". The Observatory. 135. Bibcode:2015Obs...135...71G. ISSN 0029-7704.
- ^ 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.
- ^ 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.