HD 156668
HD 156668 is a star in the northern constellation of Hercules constellation. With an apparent visual magnitude of 8.4 it is too faint to be viewed with the naked eye, but it can be seen with even a small telescope. The distance to this object has been determined directly using the parallax technique, yielding a value of about 80 light-years (25 parsecs).
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Hercules |
| Right ascension | 17h 17m 40.49053s |
| Declination | +29° 13.6′ 38.0243″ |
| Apparent magnitude (V) | +8.424 |
| Characteristics | |
| Spectral type | K3 V |
| U−B color index | 0.27 |
| B−V color index | 1.015 |
| Astrometry | |
| Radial velocity (Rv) | -9.427 km/s |
| Proper motion (μ) | RA: -72.481±0.016 mas/yr Dec.: +216.849±0.019 mas/yr |
| Parallax (π) | 41.1103 ± 0.0169 mas |
| Distance | 79.34 ± 0.03 ly (24.325 ± 0.010 pc) |
| Absolute magnitude (MV) | 6.480 |
| Details | |
| Mass | 0.772 ± 0.020 M☉ |
| Radius | 0.720 ± 0.013 R☉ |
| Luminosity | 0.230 ± 0.018 L☉ |
| Surface gravity (log g) | 4.60 ± 0.12 cgs |
| Temperature | 4850 ± 88 K |
| Metallicity [Fe/H] | +0.05 ± 0.06 dex |
| Rotation | 51.5 days |
| Rotational velocity (v sin i) | 0.50 ± 1.0 km/s |
| Age | 8.6 ± 4.8 Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
This star has the stellar classification of a K2 dwarf, with approximately 77% of the mass of the Sun and about 72% of the Sun's diameter. While they are on the main sequence, lower mass stars like this generate energy much more slowly than the Sun. As a result, this star is radiating only 23% of the Sun's bolometric luminosity. HD 156668 is emitting this energy from its outer atmosphere at an effective temperature of around 4850 K, giving it the cool orange glow of a K-type star. It is slightly more enriched in iron compared to the Sun and is rotating at a leisurely rate of once every 51.5 days. Although much older than the Sun, this star is only middle-aged at about 8.6 billion years.
The HD 156668 exhibits a stellar activity cycle with a period about 10 years.