Theta Aquarii
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Aquarius |
| Right ascension | 22h 16m 50.037s |
| Declination | −07° 46′ 59.84″ |
| Apparent magnitude (V) | 4.175 |
| Characteristics | |
| Spectral type | G8 III–IV |
| U−B color index | +0.818 |
| B−V color index | +0.983 |
| Astrometry | |
| Radial velocity (Rv) | −13.77±0.17 km/s |
| Proper motion (μ) | RA: +118.929 mas/yr Dec.: −21.928 mas/yr |
| Parallax (π) | 17.0893±0.1471 mas |
| Distance | 191 ± 2 ly (58.5 ± 0.5 pc) |
| Absolute magnitude (MV) | +0.23 |
| Details | |
| Mass | 2.39 to 2.78 M☉ |
| Radius | 12 R☉ |
| Luminosity | 72 to 83 L☉ |
| Surface gravity (log g) | 2.8 cgs |
| Temperature | 4,864 K |
| Metallicity [Fe/H] | +0.01 to +0.09 dex |
| Rotational velocity (v sin i) | 1.6 km/s |
| Age | 437 Myr |
| Other designations | |
| Ancha, θ Aquarii, Tet Aqr, θ Aqr, 43 Aquarii, BD−08 5845, FK5 840, HD 211391, HIP 110003, HR 8499, SAO 145991 | |
| Database references | |
| SIMBAD | data |
Theta Aquarii is a star in the equatorial constellation of Aquarius. Its identifier is a Bayer designation that is Latinized from θ Aquarii, and abbreviated Tet Aqr or θ Aqr, respectively. It has the official name Ancha, which is pronounced /ˈæŋkə/. Visible to the naked eye at an apparent visual magnitude of 4.175, it is located at a distance of around 191 light-years (59 parsecs) from the Sun. The star is drifting closer to the Sun with a radial velocity of −14 km/s. Since it is near the ecliptic it can be occulted by the Moon, or very rarely by planets.