HD 158614
HD 158614 is a visual binary star system in the equatorial constellation of Ophiuchus. The system is visible to the naked eye with a combined apparent visual magnitude of +5.31. It is located at a distance of 53.3 light years from the Sun based on parallax, but is drifting closer with a radial velocity of −77 km/s and is predicted to come to within 11.0 light-years in around 196,000 years. The system has been included as a candidate member of the Zeta Herculis moving group. However, chemical abundances appear to rule that out.
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Ophiuchus |
| Right ascension | 17h 30m 23.79699s |
| Declination | −01° 03′ 46.4882″ |
| Apparent magnitude (V) | +5.31 (6.02 + 5.93) |
| Characteristics | |
| Evolutionary stage | Subgiant |
| Spectral type | G9IV-V + G9IV-V |
| B−V color index | +0.715±0.013 |
| Astrometry | |
| Radial velocity (Rv) | −76.98±0.05 km/s |
| Proper motion (μ) | RA: −127.77 mas/yr Dec.: −168.61 mas/yr |
| Parallax (π) | 61.19 ± 0.68 mas |
| Distance | 53.3 ± 0.6 ly (16.3 ± 0.2 pc) |
| Absolute magnitude (MV) | 4.24 |
| Orbit | |
| Period (P) | 46.34±0.021 yr |
| Semi-major axis (a) | 977.±3.3 mas |
| Eccentricity (e) | 0.168±0.0025 |
| Inclination (i) | 99.1±0.11° |
| Longitude of the node (Ω) | 332.3±0.13° |
| Periastron epoch (T) | 1870.0±0.16 Byr |
| Argument of periastron (ω) (secondary) | 148.±1.3° |
| Details | |
| A | |
| Mass | 0.963±0.005 M☉ |
| Radius | 1.7 R☉ |
| Luminosity | 2.5 L☉ |
| Surface gravity (log g) | 4.00 cgs |
| Temperature | 5,500±150 K |
| Age | 12.3 Gyr |
| B | |
| Mass | 0.951±0.005 M☉ |
| Other designations | |
| Database references | |
| SIMBAD | data |
The pair were found to be a double star by F. G. W. Struve in 1827 and given the catalogue identifier Σ 2173 (now STF 2173). Since then it has completed multiple orbits, yielding orbital elements showing a period of 46.3 years and an eccentricity of 0.17. The two components have similar spectra that match a stellar classification of G9IV-V. They show almost no luminosity variation; one of the pair appears to vary by 0.002 in magnitude. Both components have a slightly lower mass than the Sun: 96% and 95%, respectively. The system is estimated to be 12.3 billion years old.
This binary was included in a search for brown dwarfs that turned up no large companions.