Location of ζ Cephei (circled) | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Cepheus |
| Right ascension | 22 10 51.277 |
| Declination | +58° 12′ 04.543″ |
| Apparent magnitude (V) | 3.35 |
| Characteristics | |
| Evolutionary stage | Red supergiant |
| Spectral type | K1.5 Ib |
| B−V color index | +1.55 |
| Variable type | Eclipsing binary? |
| Astrometry | |
| Proper motion (μ) | RA: 13.359±0.148 mas/yr Dec.: 5.275±0.183 mas/yr |
| Parallax (π) | 3.2972 ± 0.1456 mas |
| Distance | 992.7+51.2 −46 ly (304.5+15.7 −14.1 pc) |
| Absolute magnitude (MV) | −4.7 |
| Details | |
| Mass | 10.1±0.1 M☉ |
| Radius | 172.7+7.5 −8.3 R☉ |
| Luminosity | 10,024±1,052 L☉ |
| Surface gravity (log g) | 0.75 cgs |
| Temperature | 4,393±58 K |
| Metallicity | +0.04 dex |
| Rotational velocity (v sin i) | 10.64 km/s |
| Other designations | |
| 21 Cephei, HR 8465, BD+57°2475, HD 210745, GCTP 5139.00, SAO 34137, FK5 836, HIP 109492, Gaia DR2 2199493438511811712, Gaia DR3 2199493438511811712 | |
| Database references | |
| SIMBAD | data |
Zeta Cephei (ζ Cep, ζ Cephei) is a red supergiant star, located about 1000 light-years away in the constellation of Cepheus. Zeta Cephei marks the left shoulder of Cepheus, the King of Ethiopia. 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, 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. The luminosity of Zeta Cephei is approximately 10,000 times that of the Sun. At a distance of about 840 light-years, 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.
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.
Possible companion star
Hekker et al. (2008) have detected a periodicity of 533 days, hinting at the possible presence of an as yet unseen companion. It is listed as a possible eclipsing binary with a very small amplitude.
References
- ^ 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.
- ^ 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.
- ^ 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.
- ^ 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.
- Bailer-Jones, C. A. L.; Rybizki, J.; Fouesneau, M.; Demleitner, M.; Andrae, R. (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.
- 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.
- ^ Machado, L. N.; Abe, K.; Hayato, Y.; Hiraide, K.; Ieki, K.; Ikeda, M.; Kameda, J.; Kanemura, Y.; Kaneshima, R.; Kashiwagi, Y.; Kataoka, Y.; Miki, S.; Mine, S.; Miura, M.; Moriyama, S. (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.
- ^ 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.
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