Back Delta Cephei Afrikaans دلتا قيفاوس Arabic Delta Cephei AST Delta Cephei BS Delta Cephei Catalan Delta Cephei Czech Delta Cephei German Delta Cephei Spanish Delta Cephei Basque دلتا قیفاووس Persian
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| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Cepheus |
| δ Cep A | |
| Right ascension | 22h 29m 10.26502s[1] |
| Declination | +58° 24′ 54.7139″[1] |
| Apparent magnitude (V) | 4.07 (3.48–4.37) / 7.5 |
| δ Cep C | |
| Right ascension | 22h 29m 09.248s[1] |
| Declination | +58° 24′ 14.76″[1] |
| Apparent magnitude (V) | 6.3 |
| Characteristics | |
| Spectral type | F5Ib-G1Ib[2] + B7-8[3] |
| U−B color index | 0.36 |
| B−V color index | 0.60 |
| Variable type | Cepheid |
| Astrometry | |
| Radial velocity (Rv) | -16.8[4] km/s |
| Proper motion (μ) | RA: +15.35[1] mas/yr Dec.: +3.52[1] mas/yr |
| Parallax (π) | 3.77 ± 0.16 mas[1] |
| Distance | 887 ± 26 ly (272 ± 8[5][6] pc) |
| Absolute magnitude (MV) | –3.47 ± 0.10 (–3.94 - –3.05)[5] |
| Details | |
| δ Cep A | |
| Mass | 4.5 ± 0.3[7] M☉ |
| Radius | 46.1+1.9 −2.1[8] R☉ |
| Luminosity | 1,949±107[9] L☉ |
| Surface gravity (log g) | 1.65[8] cgs |
| Temperature | 5,536±34[9] K |
| Metallicity [Fe/H] | +0.08[10] dex |
| Rotational velocity (v sin i) | 9[11] km/s |
| δ Cep B[4] | |
| Mass | 0.2 - 1.2 M☉ |
| δ Cep C | |
| Luminosity | 500 L☉ |
| Temperature | 8,800[7] K |
| Orbit[4] | |
| Primary | δ Cep A |
| Companion | δ Cep B |
| Period (P) | 6.03 yr |
| Eccentricity (e) | 0.647 |
| Semi-amplitude (K1) (primary) | 1.509 ± 0.2 km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
Delta Cephei (δ Cep, δ Cephei) is a quadruple star system[4] located approximately 887 light-years away in the northern constellation of Cepheus, the King. At this distance, the visual magnitude of the star is diminished by 0.23 as a result of extinction caused by gas and dust along the line of sight.[5] It is the prototype of the Cepheid variable stars that undergo periodic changes in luminosity.
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