Kappa Ursae Majoris
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Ursa Major |
| Right ascension | 09h 03m 37.52762s |
| Declination | +47° 09′ 23.4890″ |
| Apparent magnitude (V) | 3.56 (4.16 + 4.54) |
| Characteristics | |
| Spectral type | A0 IV-V + A0 V |
| Astrometry | |
| Proper motion (μ) | RA: −36.19 mas/yr Dec.: −55.40 mas/yr |
| Parallax (π) | 9.10±0.50 mas |
| Distance | 360 ± 20 ly (110 ± 6 pc) |
| Absolute magnitude (MV) | −1.63 |
| Orbit | |
| Period (P) | 13,007.2±9.7 d |
| Semi-major axis (a) | 0.18194 ± 0.00025″ |
| Eccentricity (e) | 0.5584±0.0015 |
| Inclination (i) | 109.410±0.066° |
| Longitude of the node (Ω) | 105.641±0.080° |
| Periastron epoch (T) | 50404 ± 12 |
| Argument of periastron (ω) (secondary) | 355.63±0.36° |
| Details | |
| κ UMa A | |
| Mass | 3.79±0.12 M☉ |
| Radius | 7.87 R☉ |
| Temperature | 9,060 K |
| Rotational velocity (v sin i) | 201 km/s |
| Other designations | |
| Alkaphrah, κ UMa, 12 Ursae Majoris, BD+47°1633, FK5 341, GC 12503, HD 77327, HIP 44471, HR 3594, SAO 42661, PPM 50987, CCDM J09036+4709AB, WDS J09036+4709AB | |
| Database references | |
| SIMBAD | data |
Kappa Ursae Majoris (κ Ursae Majoris, abbreviated Kappa UMa, κ UMa) is a binary star in the constellation of Ursa Major. With a combined apparent magnitude of +3.60, the system is approximately 358 light-years from Earth.
The two components are designated Kappa Ursae Majoris A (officially named Alkaphrah /ælˈkæfrə/, a traditional name of the system) and B.