HD 171238
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Sagittarius |
| Right ascension | 18h 34m 43.676s |
| Declination | −28° 04′ 20.33″ |
| Apparent magnitude (V) | 8.606 |
| Characteristics | |
| Evolutionary stage | Main sequence |
| Spectral type | G8 V |
| Apparent magnitude (B) | 9.40 |
| Apparent magnitude (J) | 7.244 |
| Apparent magnitude (H) | 6.868 |
| Apparent magnitude (K) | 6.831 |
| B−V color index | 0.74 |
| Astrometry | |
| Radial velocity (Rv) | 21.11±0.17 km/s |
| Proper motion (μ) | RA: −29.539 mas/yr Dec.: −109.580 mas/yr |
| Parallax (π) | 22.4809±0.0324 mas |
| Distance | 145.1 ± 0.2 ly (44.48 ± 0.06 pc) |
| Absolute magnitude (MV) | 5.15 |
| Details | |
| Mass | 0.99±0.01 M☉ |
| Radius | 0.95±0.01 R☉ |
| Luminosity | 0.774±0.003 L☉ |
| Surface gravity (log g) | 4.47±0.01 cgs |
| Temperature | 5,570±21 K |
| Metallicity [Fe/H] | 0.17±0.007 dex |
| Rotational velocity (v sin i) | 1.48 km/s |
| Age | 4.0±1.2 Gyr |
| Other designations | |
| CD–28°14719, HD 171238, HIP 91085, SAO 186998, PPM 268605 | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
HD 171238 is a star with an orbiting exoplanet in the southern constellation of Sagittarius. It is located at a distance of 145 light years from the Sun based on parallax measurements, and is drifting further away with a radial velocity of 21 km/s. The star has an absolute magnitude of 5.15, but at the distance of this system it is too faint to be viewed with the naked eye, having an apparent visual magnitude of 8.61.
The spectrum of HD 171238 presents as an ordinary G-type main-sequence star with a stellar classification of G8 V. At an estimated age of around four billion years, it is spinning with a projected rotational velocity of 1.5 km/s. The metallicity of the star – the abundance of elements more massive than helium – is 48% higher than solar, based on the abundance of iron. There are indications of a significant level of magnetic activity in the chromosphere. The star has 99% of the mass of the Sun and 95% of the Sun's girth. It is radiating just 77% of the luminosity of the Sun from its photosphere at an effective temperature of 5,570 K.