Pi Aquarii
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Aquarius |
| Right ascension | 22h 25m 16.623s |
| Declination | +01° 22′ 38.63″ |
| Apparent magnitude (V) | 4.42 - 4.87 |
| Characteristics | |
| Spectral type | B1III-IVe |
| U−B color index | −0.98 |
| B−V color index | −0.03 |
| Variable type | γ Cas |
| Astrometry | |
| Radial velocity (Rv) | +4.0 km/s |
| Proper motion (μ) | RA: +17.518 mas/yr Dec.: +2.563 mas/yr |
| Parallax (π) | 2.9761±0.1129 mas |
| Distance | 1,100 ± 40 ly (340 ± 10 pc) |
| Absolute magnitude (MV) | −2.09 |
| Orbit | |
| Period (P) | 84.07±0.02 d |
| Semi-major axis (a) | ≥ 0.96 AU |
| Eccentricity (e) | 0.0 (fixed) |
| Periastron epoch (T) | 2,450,318.5±13.2 JD |
| Argument of periastron (ω) (secondary) | 0.0 (fixed)° |
| Semi-amplitude (K1) (primary) | 16.7±0.2 km/s |
| Semi-amplitude (K2) (secondary) | 101.4±0.2 km/s |
| Details | |
| A | |
| Mass | 11.0±0.9 M☉ |
| Radius | 5.75±0.99 (equatorial) 5.00±0.81 (polar) R☉ |
| Luminosity | 8,300+1,700 −1,400 L☉ |
| Surface gravity (log g) | 3.96±0.11 (equatorial) 3.96±0.11 (polar) cgs |
| Temperature | 22,400±1,400 (equatorial) 25,000±1,000 (polar) K |
| Metallicity [Fe/H] | −0.02 dex |
| Rotational velocity (v sin i) | 271±13 km/s |
| Age | 10.0±5.0 Myr |
| B | |
| Mass | 0.5–0.8 M☉ |
| Other designations | |
| π Aqr, 52 Aquarii, BD+00 4872, FK5 1585, HD 212571, HIP 110672, HR 8539, SAO 127520 | |
| Database references | |
| SIMBAD | data |
Pi Aquarii is a binary star system in the equatorial constellation of Aquarius. Its name is a Bayer designation that is Latinized from π Aquarii, and abbreviated Pi Aqr or π Aqr. This system has a combined apparent visual magnitude of +4.57, which is bright enough to be faintly visible to the naked eye. Based upon parallax measurements, it is located at a distance of approximately 1,100 light-years (340 parsecs) from the Sun. It is drifting further away with a radial velocity of +4 km/s.