Beta Herculis
Binary star in the northern constellation of Hercules / From Wikipedia, the free encyclopedia
Beta Herculis (β Herculis, abbreviated Beta Her, β Her), formally named Kornephoros /kɔːrˈnɛfərəs/,[12] or Rutilicus, is a binary star and the brightest star in the northern constellation of Hercules[13] 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.[14] Based upon parallax measurements, it is located at a distance of 139 light-years (43 parsecs) from the Sun.[1]
Quick Facts Constellation, Right ascension ...
Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
---|---|
Constellation | Hercules |
Right ascension | 16h 30m 13.19955s[1] |
Declination | +21° 29′ 22.6008″[1] |
Apparent magnitude (V) | 2.81[2] |
Characteristics | |
Spectral type | G7 IIIa[3] |
U−B color index | +0.70[2] |
B−V color index | +0.91[2] |
R−I color index | +0.47[4] |
Astrometry | |
Radial velocity (Rv) | −25.5[5] km/s |
Proper motion (μ) | RA: −99.15[1] mas/yr Dec.: −15.39[1] mas/yr |
Parallax (π) | 23.44 ± 0.58 mas[1] |
Distance | 139 ± 3 ly (43 ± 1 pc) |
Absolute magnitude (MV) | −0.49 ± 0.10[6] |
Details | |
A | |
Mass | 2.9[7] M☉ |
Radius | 17[8] R☉ |
Luminosity | 151[8] L☉ |
Surface gravity (log g) | 2.5[8] cgs |
Temperature | 4,887[8] K |
Metallicity [Fe/H] | –0.27[8] dex |
Rotational velocity (v sin i) | 3.0[8] km/s |
B | |
Mass | 0.9[7] M☉ |
Orbit[9] | |
Period (P) | 410.6 d |
Semi-major axis (a) | 11.37 ± 0.51 mas |
Eccentricity (e) | 0.55 |
Inclination (i) | 53.8 ± 2.3° |
Longitude of the node (Ω) | 341.9 ± 3.8° |
Periastron epoch (T) | 15500.4 MJD |
Argument of periastron (ω) (primary) | 24.6° |
Other designations | |
Database references | |
SIMBAD | data |
Close
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.[15]