46 Boötis
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Boötes |
| Right ascension | 15h 08m 23.78241s |
| Declination | +26° 18′ 04.1464″ |
| Apparent magnitude (V) | 5.67 |
| Characteristics | |
| Spectral type | K2 III |
| U−B color index | +1.24 |
| B−V color index | +1.240±0.015 |
| Astrometry | |
| Radial velocity (Rv) | +19.31±0.30 km/s |
| Proper motion (μ) | RA: +4.454 mas/yr Dec.: −15.185 mas/yr |
| Parallax (π) | 6.8288±0.0883 mas |
| Distance | 478 ± 6 ly (146 ± 2 pc) |
| Absolute magnitude (MV) | −0.31 |
| Orbit | |
| Period (P) | 2,567.1±0.6 d |
| Semi-major axis (a) | 11.2 mas |
| Eccentricity (e) | 0.8315±0.0027 |
| Inclination (i) | 62° |
| Longitude of the node (Ω) | 82.6±6.6° |
| Periastron epoch (T) | 2,448,356.6 JD |
| Argument of periastron (ω) (secondary) | 175.3±0.7° |
| Semi-amplitude (K1) (primary) | 9.25±0.10 km/s |
| Details | |
| 46 Boo A | |
| Radius | 23.35+0.85 −0.67 R☉ |
| Luminosity | 175.8±2.8 L☉ |
| Temperature | 4,349+64 −76 K |
| Metallicity [Fe/H] | −0.27±0.15 dex |
| Other designations | |
| b Boo, 46 Boo, BD+26°2656, FK5 1396, GC 20367, HD 134320, HIP 74087, HR 5638, SAO 83682 | |
| Database references | |
| SIMBAD | data |
46 Boötis is a binary star system in the northern constellation of Boötes, located mid-way between α Coronae Borealis and ε Boötis. It has the Bayer designation b Boötis; 46 Boötis is the Flamsteed designation. The system lies 478 light-years away from the Sun based on parallax, and is visible to the naked eye as a faint, orange-hued star with a combined apparent visual magnitude of 5.67. It is moving away from the Earth with a heliocentric radial velocity of +19 km/s. The light from this system displays an unusually high level of polarization due to interstellar dust.
This is a single-lined spectroscopic binary with an orbital period of 7.03 years and a large eccentricity of 0.83. The primary member, designated component A, is an aging giant star with a stellar classification of K2 III. As a consequence of exhausting the hydrogen at its core, it has expanded to 23 times the Sun's radius. It is radiating 176 times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 4,349 K. The companion star, component B, is most likely a lower main-sequence star with 0.6–0.8 times the Sun's mass.