Zeta Aquarii
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Aquarius |
| ζ Aqr A | |
| Right ascension | 22h 28m 49.888s |
| Declination | −00° 01′ 11.87″ |
| Apparent magnitude (V) | 4.42 |
| ζ Aqr B | |
| Right ascension | 22h 28m 49.886s |
| Declination | −00° 01′ 13.96″ |
| Apparent magnitude (V) | 4.51 |
| Characteristics | |
| Spectral type | F3 V + F6 IV |
| U−B color index | −0.01 |
| B−V color index | +0.40 |
| Astrometry | |
| ζ Aqr A | |
| Radial velocity (Rv) | +24.9 km/s |
| Proper motion (μ) | RA: +180.832 mas/yr Dec.: +33.072 mas/yr |
| Parallax (π) | 34.5070±0.4712 mas |
| Distance | 95 ± 1 ly (29.0 ± 0.4 pc) |
| Absolute magnitude (MV) | 1.15 |
| ζ Aqr B | |
| Radial velocity (Rv) | +28.9 km/s |
| Proper motion (μ) | RA: +224.295 mas/yr Dec.: +25.396 mas/yr |
| Parallax (π) | 34.4525 ± 0.3109 mas |
| Distance | 94.7 ± 0.9 ly (29.0 ± 0.3 pc) |
| Orbit | |
| Primary | ζ Aqr Aa |
| Companion | ζ Aqr Ab |
| Period (P) | 25.95±0.048 yr |
| Semi-major axis (a) | 0.385″ |
| Eccentricity (e) | 0.872±0.006 |
| Inclination (i) | 11.8±6.7° |
| Longitude of the node (Ω) | 293.7±74° |
| Periastron epoch (T) | B 2006.52±0.13 |
| Argument of periastron (ω) (secondary) | 100.9±73° |
| Orbit | |
| Primary | ζ Aqr A |
| Companion | ζ Aqr B |
| Period (P) | 540±15 yr |
| Semi-major axis (a) | 3.496±0.046″ |
| Eccentricity (e) | 0.419±0.011 |
| Inclination (i) | 142.0±0.4° |
| Longitude of the node (Ω) | 131.3±0.8° |
| Periastron epoch (T) | B 1981.50±0.58 |
| Argument of periastron (ω) (secondary) | 269.3±1.7° |
| Details | |
| ζ Aqr Aa | |
| Mass | 1.4 M☉ |
| Metallicity [Fe/H] | −0.13 dex |
| Rotational velocity (v sin i) | 62 km/s |
| Age | 3 Gyr |
| ζ Aqr Ab | |
| Mass | 0.6 M☉ |
| ζ Aqr B | |
| Mass | 1.4 M☉ |
| Rotational velocity (v sin i) | 56 km/s |
| Other designations | |
| ζ Aquarii, ζ Aqr, Zet Aqr, 55 Aquarii, BD−00°4365, HIP 110960, ADS 15971 | |
| ζ Aqr A: ζ2 Aquarii, Zeta2 Aquarii, HD 213052, HR 8559, SAO 146108 | |
| ζ Aqr B: ζ1 Aquarii, Zeta1 Aquarii, HD 213051, HR 8558, SAO 146107 | |
| Database references | |
| SIMBAD | ζ Aqr |
| ζ Aqr A | |
| ζ Aqr B | |
Zeta Aquarii is a triple star system, the central star of the "water jar" asterism in the equatorial constellation of Aquarius. Its identifier is a Bayer designation that is Latinized from ζ Aquarii, and abbreviated Zet Aqr or ζ Aqr, respectively. The combined apparent visual magnitude of this system is 3.65, which is readily visible to the naked eye. Parallax measurements yield a distance estimate of around 95 light-years (29 parsecs) from Earth.