| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Boötes |
| Right ascension | 13h39m 34.61613s[1] |
| Declination | +10° 44′ 46.5827″[1] |
| Apparent magnitude (V) | 5.57[2] (6.35 + 6.47)[3] |
| Characteristics | |
| Evolutionary stage | Main sequence[4][5] |
| Spectral type | F0V[6] |
| U−B color index | +0.045[7] |
| B−V color index | +0.33[7] |
| Astrometry | |
| Radial velocity (Rv) | −25.9±1.9[8] km/s |
| Proper motion (μ) | RA: −114.96[1] mas/yr Dec.: −11.74[1] mas/yr |
| Parallax (π) | 16.67 ± 0.58 mas[1] |
| Distance | 196 ± 7 ly (60 ± 2 pc) |
| Absolute magnitude (MV) | +2.40[9] |
| Orbit[10] | |
| Period (P) | 22.460±0.019 yr |
| Semi-major axis (a) | 0.19983±0.00055″ |
| Eccentricity (e) | 0.5450±0.0022 |
| Inclination (i) | 43.50±0.40° |
| Longitude of the node (Ω) | 34.58±0.52° |
| Periastron epoch (T) | B 1929.850±0.024 |
| Argument of periastron (ω) (secondary) | 359.93±0.79° |
| Details | |
| A | |
| Mass | 1.89±0.03 M☉[5] 1.41[11] M☉ |
| Luminosity | 18.5[5] L☉ |
| Surface gravity (log g) | 3.97[11] cgs |
| Temperature | 7,080±241[11] K |
| Rotational velocity (v sin i) | 144[5] km/s |
| Age | 718[11] Myr |
| Other designations | |
BD+11° 2589, HD 118889, HIP 66640, HR 5138, SAO 100654, ADS 8987, WDS 13396+1045, BU 612 | |
| Database references | |
| SIMBAD | data |
HD 118889 is a binary star system in the northern constellationofBoötes. It is faintly visible to the naked eye as a point of light with an apparent visual magnitude of 5.57.[2] The system is located at a distance of approximately 196 light years from the Sun based on stellar parallax,[1] but is drifting closer with a radial velocity of −26 km/s.[8]
The binary components of this system were first measured by S. W. Burnham in 1878 and it was given the discovery code BU 612.[12] The pair are orbiting each other with a period of 22.46 years with an eccentricity (ovalness) of 0.545. The primary component is a magnitude 6.35[3] star with a stellar classification of F0V,[6] matching an F-type main-sequence star. It is an estimated 718[11] million years old and is spinning rapidly with a projected rotational velocity of 144[5] km/s. The star has 1.4–1.9 times the mass of the Sun. The secondary is slightly fainter at magnitude 6.47.[3]
