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 (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.
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]