HD 212771
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Aquarius |
| Right ascension | 22h 27m 03.072s |
| Declination | −17° 15′ 49.164″ |
| Apparent magnitude (V) | 7.6±0.01 |
| Characteristics | |
| Spectral type | G8 IV |
| U−B color index | +0.54 |
| B−V color index | +0.88 |
| Astrometry | |
| Radial velocity (Rv) | 14.9±0.03 km/s |
| Proper motion (μ) | RA: −85.892 mas/yr Dec.: −104.042 mas/yr |
| Parallax (π) | 8.9648±0.0314 mas |
| Distance | 364 ± 1 ly (111.5 ± 0.4 pc) |
| Absolute magnitude (MV) | 2.04 |
| Details | |
| Mass | 1.42±0.07 M☉ |
| Radius | 4.44±0.13 R☉ |
| Luminosity | 11.67±0.57 L☉ |
| Surface gravity (log g) | 3.263±0.010 cgs |
| Temperature | 5,065±75 K |
| Metallicity [Fe/H] | −0.09±0.01 dex |
| Age | 2.90±0.47 Gyr |
| Other designations | |
| BD−17°6526, HD 212771, HIP 110813, SAO 165086 | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
HD 212771, also named Lionrock, is a solitary star in the southern zodiac constellation Aquarius. It has an apparent magnitude of 7.60, making it readily visible with binoculars but not the naked eye. Parallax measurements place the object at a distance of 364 light-years, and is currently receding with a radial velocity of 15 km/s.
HD 212771 has a stellar classification of G8 IV, indicating that it is a subgiant evolving towards the red giant branch after being an F-type main-sequence star for 1.7 billion years. It has 142% the mass of the Sun and 4.4 times its radius. It radiates at 11.67 solar luminosities from its slightly enlarged photosphere at an effective temperature of 5,065 K, giving it a yellow-hue. Unlike most planetary hosts, HD 212771 is slightly metal deficient, and spins with a projected rotational velocity of about 2 km/s.