| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Cepheus |
| Right ascension | 21h27m 46.14144s[1] |
| Declination | +66° 48′ 32.7406″[1] |
| Apparent magnitude (V) | 5.42[2] |
| Characteristics | |
| Evolutionary stage | main sequence[3] |
| Spectral type | B7 V[4] |
| B−V color index | −0.099±0.004[2] |
| Astrometry | |
| Radial velocity (Rv) | +3.0±4.2[5] km/s |
| Proper motion (μ) | RA: −11.296[1] mas/yr Dec.: −19.787[1] mas/yr |
| Parallax (π) | 3.9653 ± 0.1148 mas[1] |
| Distance | 820 ± 20 ly (252 ± 7 pc) |
| Absolute magnitude (MV) | −1.54[2] |
| Details | |
| Mass | 4.47±0.07[3] M☉ |
| Radius | 3.0[6] R☉ |
| Luminosity | 769+94 −84[3] L☉ |
| Surface gravity (log g) | 3.56[7] cgs |
| Temperature | 12,560+87 −86[3] K |
| Metallicity [Fe/H] | −0.36[7] dex |
| Rotational velocity (v sin i) | 236[3] km/s |
| Age | 38[8] Myr |
| Other designations | |
7 Cep, BD+66°1405, FK5 3718, HD 204770, HIP 105972, HR 8227, SAO 19432[9] | |
| Database references | |
| SIMBAD | data |
7 Cephei is a single[10] star located approximately 820 light years away, in the northern circumpolar constellationofCepheus. It is visible to the naked eye as a dim, blue-white hued star with an apparent visual magnitude of 5.42.[2]
This is a B-type main-sequence star with a stellar classification of B7 V.[4] It is a candidate variable star with an amplitude of 9 micromagnitudes and a period of 0.737±0.002 d.[11] This object has 4.5[3] times the mass of the Sun and about three[6] times the Sun's radius. It is spinning rapidly with a projected rotational velocity of 236 km/s.[3] 7 Cephei is radiating 769[3] times the luminosity of the Sun from its photosphere at an effective temperature of 12,560 K.[3]
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