39 Boötis
Star in the constellation Boötes
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39 Boötis is a triple star[3] system located around 224[1] light years away from the Sun in the northern constellation of Boötes.[10] It is visible to the naked eye as a faint, yellow-white hued star with a combined apparent magnitude of 5.68.[2] The system is moving closer to the Earth with a heliocentric radial velocity of −31 km/s.[5]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Boötes |
| Right ascension | 14h 49m 41.29265s[1] |
| Declination | +48° 43′ 14.9077″[1] |
| Apparent magnitude (V) | 5.68[2] (6.36 + 6.72)[3] |
| Characteristics | |
| Spectral type | F8V + F7V[4] |
| Astrometry | |
| Radial velocity (Rv) | −30.9±0.3[5] km/s |
| Proper motion (μ) | RA: −77.94[1] mas/yr Dec.: 100.83[1] mas/yr |
| Parallax (π) | 14.58±0.51 mas[1] |
| Distance | 224 ± 8 ly (69 ± 2 pc) |
| Absolute magnitude (MV) | 2.53[6] |
| Orbit[7] | |
| Period (P) | 12.822 d |
| Eccentricity (e) | 0.39 |
| Periastron epoch (T) | 2,422,379.49 JD |
| Argument of periastron (ω) (secondary) | 97.1° |
| Semi-amplitude (K1) (primary) | 58.3 km/s |
| Semi-amplitude (K2) (secondary) | 72.2 km/s |
| Details | |
| 39 Boo A | |
| Mass | 1.29/1.05[8] M☉ |
| Metallicity [Fe/H] | 0.06[9] dex |
| Rotational velocity (v sin i) | 161.0[6] km/s |
| Age | 1.30[9] Gyr |
| 39 Boo B | |
| Mass | 1.25[8] M☉ |
| Other designations | |
| 39 Boo, AG+48°1158, BD+49°2326, HD 131041, HIP 72524, HR 5538, SAO 45231, CCDM J14497+4843, WDS J14497+4843[10] | |
| Database references | |
| SIMBAD | data |
The magnitude 6.36[3] primary, component A, is actually a double-lined spectroscopic binary system with an orbital period of 12.822 days, an eccentricity of 0.39,[7] and an angular separation of 2.021 mas. It has a combined stellar classification of F8V,[4] matching an F-type main-sequence star, with individual massed of 1.29 and 1.05[8] times the mass of the Sun. Component B is of magnitude 6.72[3] with a class of F7V[4] and 1.25[8] solar masses. The A–B pair have a separation of 2.9″ and a period of 1,347.653 years.[8] This system is a source of X-ray emission with a luminosity of 41.4×1028 erg s−1.[11]
It was a transferred by Jérôme Lalande from Boötes to Quadrans Muralis.[12] Later when the International Astronomical Union officially recognised constellations, Quadrans Muralis became obsolete, so this star was moved back to Boötes.