Zeta Cephei
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Cepheus |
| Right ascension | 22h 10m 51.277s |
| Declination | +58° 12′ 04.54″ |
| 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 [Fe/H] | +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.