Kappa Scorpii
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Scorpius |
| Right ascension | 17h 42m 29.27520s |
| Declination | −39° 01′ 47.9391″ |
| Apparent magnitude (V) | 2.41 - 2.42 |
| Characteristics | |
| Spectral type | B1.5 III |
| U−B color index | −0.914 |
| B−V color index | −0.228 |
| Variable type | β Cephei |
| Astrometry | |
| Radial velocity (Rv) | −14.0 km/s |
| Proper motion (μ) | RA: −6.05 mas/yr Dec.: −25.54 mas/yr |
| Parallax (π) | 6.75±0.17 mas |
| Distance | 480 ± 10 ly (148 ± 4 pc) |
| Absolute magnitude (MV) | −3.46 |
| Orbit | |
| Period (P) | 195.458±0.007 days |
| Semi-major axis (a) | 10.91±0.12 mas |
| Eccentricity (e) | 0.520±0.006 |
| Inclination (i) | 102.3±0.2° |
| Longitude of the node (Ω) | 281.96±0.12° |
| Periastron epoch (T) | 2449983.23±0.4 |
| Argument of periastron (ω) (secondary) | 87.6±0.6° |
| Semi-amplitude (K1) (primary) | 48.0±0.3 km/s |
| Details | |
| κ Sco A | |
| Mass | 11.1±1.7 M☉ |
| Radius | 6.8 R☉ |
| Luminosity | 6,911 L☉ |
| Surface gravity (log g) | 4.01 cgs |
| Temperature | 23,400 K |
| Rotation | 1.90 days |
| Rotational velocity (v sin i) | 105 km/s |
| Age | 25.1±1.3 Myr |
| κ Sco B | |
| Mass | 10.0±1.1 M☉ |
| Radius | 5.8 R☉ |
| Surface gravity (log g) | 4.00 cgs |
| Temperature | 18,800 K |
| Other designations | |
| Girtab, κ Sco, CD−38°12137, CPD−38°6992, FK5 660, HD 160578, HIP 86670, HR 6580, SAO 209163 | |
| Database references | |
| SIMBAD | data |
Kappa Scorpii, Latinized from κ Scorpii, is a binary star system in the southern constellation of Scorpius. With an apparent visual magnitude of 2.4, this star system is readily visible to the naked eye. Parallax measurements place it at an estimated distance of roughly 480 light-years (150 parsecs) from the Earth.