Beta Herculis
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Hercules |
| Right ascension | 16h 30m 13.19955s |
| Declination | +21° 29′ 22.6008″ |
| Apparent magnitude (V) | 2.81 |
| Characteristics | |
| Evolutionary stage | Red clump |
| Spectral type | G7 IIIa |
| U−B color index | +0.70 |
| B−V color index | +0.91 |
| R−I color index | +0.47 |
| Astrometry | |
| Radial velocity (Rv) | −25.5 km/s |
| Proper motion (μ) | RA: −99.15 mas/yr Dec.: −15.39 mas/yr |
| Parallax (π) | 23.44±0.58 mas |
| Distance | 139 ± 3 ly (43 ± 1 pc) |
| Absolute magnitude (MV) | −0.49 ± 0.10 |
| Details | |
| A | |
| Mass | 2.91±0.11 M☉ |
| Radius | 15.92+0.39 −0.41 R☉ |
| Luminosity | 153.7±0.8 L☉ |
| Surface gravity (log g) | 2.5 cgs |
| Temperature | 5,092±64 K |
| Metallicity [Fe/H] | −0.115 dex |
| Rotational velocity (v sin i) | 3.0 km/s |
| Age | 420±60 Myr |
| B | |
| Mass | 0.9 M☉ |
| Orbit | |
| Period (P) | 1.1254±0.0001 years |
| Semi-major axis (a) | 11.37 ± 0.51 mas 0.504±0.034 AU |
| Eccentricity (e) | 0.5613±0.0010 |
| Inclination (i) | 53.8 ± 2.3° |
| Longitude of the node (Ω) | 341.9 ± 3.8° |
| Periastron epoch (T) | 3310.9±9.3 JD |
| Argument of periastron (ω) (primary) | 21.9±0.05° |
| Semi-amplitude (K1) (primary) | 13.05±0.05 km/s |
| Other designations | |
| Kornephoros, Korndeforos, Rutilicus, β Her, Beta Herculis, Beta Her, 27 Herculis, 27 Her, BD+21 2934, FK5 618, HD 148856, HIP 80816, HR 6148, SAO 84411, WDS 16302+2129A/Aa. | |
| Database references | |
| SIMBAD | data |
Beta Herculis (β Herculis, abbreviated Beta Her, β Her), formally named Kornephoros /kɔːrˈnɛfərəs/, is a binary star and the brightest star in the northern constellation of Hercules at a base apparent visual magnitude of 2.81. This is a suspected variable star with an apparent magnitude that may rise as high as 2.76. Based upon parallax measurements, it is located at a distance of 139 light-years (43 parsecs) from the Sun.
Although Beta Herculis appears to the naked eye to be a single star, in July 1899 the American astronomer W. W. Campbell discovered from spectroscopic measurements that its radial velocity varies, and concluded that it has a companion.