91 Aquarii
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Aquarius |
| Right ascension | 23h 15m 53.49405s |
| Declination | −09° 05′ 15.8450″ |
| Apparent magnitude (V) | +4.248 |
| Characteristics | |
| Spectral type | K1 III |
| U−B color index | +1.035 |
| B−V color index | +1.104 |
| R−I color index | 0.56 |
| Astrometry | |
| Radial velocity (Rv) | −26.07±0.13 km/s |
| Proper motion (μ) | RA: +369.477 mas/yr Dec.: −16.981 mas/yr |
| Parallax (π) | 22.0924±0.1302 mas |
| Distance | 147.6 ± 0.9 ly (45.3 ± 0.3 pc) |
| Absolute magnitude (MV) | 0.919 |
| Details | |
| Mass | 0.774±0.150 M☉ 1.004±0.175 M☉ 1.4±0.1 M☉ 1.76±0.21 M☉ |
| Radius | 10.8±0.2 R☉ |
| Luminosity | 48±3 L☉ |
| Surface gravity (log g) | 2.32±0.11 cgs |
| Temperature | 4,631±69 K |
| Metallicity [Fe/H] | −0.03±0.01 dex |
| Rotational velocity (v sin i) | 1.49±0.45 km/s |
| Age | 1.54±0.46 Gyr 3.56±0.63 Gyr 9.2±5.1 Gyr |
| Other designations | |
| Psi1 Aquarii, ADS 16633, Gl 893.2, WDS J23159-0905 | |
| A: BD−09 6156, FK5 1608, HD 219449, HIP 114855, HR 8841, LTT 9437, SAO 146598 | |
| BC: BD−09 6155, HD 219430, LTT 9434, SAO 146596 | |
| Database references | |
| SIMBAD | A |
| BC | |
91 Aquarii is a triple star system in the equatorial constellation of Aquarius. It also bears the Bayer designation Psi1 Aquarii (ψ1 Aqr, ψ1 Aquarii). It is visible to the naked eye with an apparent visual magnitude of +4.248. Parallax measurements yield an estimated distance of around 150 light-years (46 parsecs) from Earth. An extrasolar planet is known to orbit the main star.