HD 159868
HD 159868 is a star in the southern constellation of Scorpius, positioned about 0.3° to the ESE of the bright star Theta Scorpii. With an apparent visual magnitude of +7.24, it is too faint to be visible to the naked eye but can be viewed with a small telescope. The star lies at a distance of 183 light years from the Sun based on parallax, but is drifting closer with a radial velocity of −24 km/s.
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Scorpius |
| Right ascension | 17h 38m 59.5264s |
| Declination | −43° 08′ 43.8443″ |
| Apparent magnitude (V) | +7.24 |
| Characteristics | |
| Spectral type | G5V |
| Apparent magnitude (J) | 5.941±0.021 |
| Apparent magnitude (H) | 5.567±0.026 |
| Apparent magnitude (K) | 5.535±0.024 |
| B−V color index | 0.714±0.012 |
| Astrometry | |
| Radial velocity (Rv) | −23.80±0.76 km/s |
| Proper motion (μ) | RA: −230.510 mas/yr Dec.: −167.766 mas/yr |
| Parallax (π) | 17.8763 ± 0.0530 mas |
| Distance | 182.5 ± 0.5 ly (55.9 ± 0.2 pc) |
| Absolute magnitude (MV) | +3.63 |
| Details | |
| Mass | 1.087+0.032 −0.033 M☉ 1.123±0.018 M☉ |
| Radius | 1.97±0.04 R☉ 2.03+0.05 −0.04 R☉ |
| Luminosity | 3.59±0.02 L☉ |
| Surface gravity (log g) | 3.96±0.02 cgs |
| Temperature | 5,558±15 K |
| Metallicity [Fe/H] | −0.08±0.01 dex |
| Rotational velocity (v sin i) | 2.1 km/s |
| Age | 6.6±0.2 Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
The spectrum of this object matches a G-type main-sequence star with a stellar classification of G5V. It has a relatively low surface gravity for its class, which suggests it is slightly evolved off the main sequence. The star is chromospherically inactive with a slow rotation rate, having a projected rotational velocity of 2.1 km/s. It is an estimated 6.6 billion years old with 8–12% more mass than the Sun and nearly double the Sun's radius. The star is radiating 3.6 times the luminosity of the Sun from its photosphere at an effective temperature of 5,558 K.