Xi Cephei
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Cepheus |
| A | |
| Right ascension | 22h 03m 47.440s |
| Declination | +64° 37′ 40.70″ |
| Apparent magnitude (V) | 4.45 (4.61 + 6.50) |
| B | |
| Right ascension | 22h 03m 46.217s |
| Declination | +64° 37′ 41.47″ |
| Apparent magnitude (V) | 6.34 |
| Characteristics | |
| A | |
| Spectral type | kA2.5hF2mF2(IV) (A3Vm + F2III) |
| B | |
| Evolutionary stage | main sequence |
| Spectral type | F8V |
| Astrometry | |
| A | |
| Radial velocity (Rv) | −7.2±2 km/s |
| Proper motion (μ) | RA: +212.563 mas/yr Dec.: +89.058 mas/yr |
| Parallax (π) | 32.12±0.8066 mas |
| Distance | 102 ± 3 ly (31.1 ± 0.8 pc) |
| B | |
| Radial velocity (Rv) | −6.2±2 km/s |
| Proper motion (μ) | RA: +202.094 mas/yr Dec.: +81/933 mas/yr |
| Parallax (π) | 32.1835±0.0184 mas |
| Distance | 101.34 ± 0.06 ly (31.07 ± 0.02 pc) |
| Orbit | |
| Period (P) | 2.245+0.001 −0.000 years |
| Semi-major axis (a) | 0.072+0.000 −0.001″ |
| Eccentricity (e) | 0.460+0.009 −0.008 |
| Inclination (i) | 67.447+0.508 −0.443° |
| Longitude of the node (Ω) | 272.995+0.702 −0.301° |
| Periastron epoch (T) | 1968.751+7 −5 |
| Argument of periastron (ω) (secondary) | 90.354+0.315 −0.418° |
| Semi-amplitude (K1) (primary) | 7.81 km/s |
| Semi-amplitude (K2) (secondary) | 19.98 km/s |
| Details | |
| Aa | |
| Mass | 1.721+0.134 −0.120 M☉ |
| Luminosity | 6.6 L☉ |
| Temperature | 7,943 K |
| Age | 200 Myr |
| Ab | |
| Mass | 0.512 M☉ |
| Luminosity | 1.8 L☉ |
| Temperature | 6,310 K |
| Age | 525 Myr |
| B | |
| Mass | 1.14 M☉ |
| Radius | 1.28 R☉ |
| Luminosity | 2.08 L☉ |
| Surface gravity (log g) | 4.26 cgs |
| Temperature | 6,123 K |
| Age | 3.98 Gyr |
| Other designations | |
| Kurhah, 17 Cephei, BD+63°1802, HIP 108917, HR 8417, SAO 19827, CCDM J22038+2407, WDS J22038+6438 | |
| A: HD 209790 | |
| B: HD 209791 | |
| Database references | |
| SIMBAD | ξ |
| A | |
| B | |
Xi Cephei is a multiple star system in the northern constellation of Cepheus. Its name is a Bayer designation. This system is visible to the naked eye as a point of light with a combined apparent visual magnitude of 4.29. Based on parallax measurements, it is located at a distance of approximately 102 light-years from Earth.
This system consists of a binary pair, designated Xi Cephei A, together with a more distant companion, Xi Cephei B. A's two components are themselves designated Xi Cephei Aa (officially named Kurhah /ˈkɜːrhə/, the traditional name of the system) and Ab.