Zeta Cephei
 Location of ζ Cephei (circled) |
|
| Observation data Epoch J2000 Equinox J2000 |
|
|---|---|
| Constellation | Cepheus |
| Right ascension | 22h 10m 51.277s[1] |
| Declination | +58° 12′ 04.55″[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: 13.52 ± 0.10[1] mas/yr Dec.: 5.24 ± 0.09[1] mas/yr |
| Parallax (π) | 3.90 ± 0.10[1] mas |
| Distance | 840 ± 20 ly (256 ± 7 pc) |
| Absolute magnitude (MV) | −4.7[5] |
| Details | |
| Radius | 230[6] R☉ |
| Luminosity | 5,660[7] L☉ |
| Surface gravity (log g) | 0.75[7] cgs |
| Temperature | 4,000[2] K |
| Metallicity [Fe/H] | +0.22[7] dex |
| Rotational velocity (v sin i) | 10.64[8] 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 an orange supergiant star with a surface temperature of 3,853 K and eight times more massive than the Sun. The luminosity of Zeta Cephei is approximately 3,600 times that of the Sun. At a distance of about 840 light-years,[1] 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.[9] It is listed as a possible eclipsing binary with a very small amplitude.[4]
At the edge of the 8 to 10 solar mass (M☉) limit at which stars develop iron cores and then explode as supernovae, Zeta Cephei's most likely fate is to produce a very massive white dwarf near the Chandrasekhar limit (1.4 M☉) at which such dense remnants can survive. If Zeta Cephei is a binary star; i.e., if there is a stellar companion, and it is close enough to feed sufficient matter to the white-dwarf-to-be, it is marginally possible that the limit could be overflowed, resulting in the white dwarf's collapse and a Type Ia supernova explosion.[citation needed]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Lua error in package.lua at line 80: module 'strict' not found.Vizier catalog entry
- ↑ 2.0 2.1 2.2 Lua error in package.lua at line 80: module 'strict' not found.
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- ↑ 4.0 4.1 Lua error in package.lua at line 80: module 'strict' not found.
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- ↑ 7.0 7.1 7.2 Lua error in package.lua at line 80: module 'strict' not found.
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