12 Aquarii
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Aquarius |
| Right ascension | 21h 04m 04.72438s |
| Declination | −05° 49′ 23.0347″ |
| Apparent magnitude (V) | 5.67 (5.88 + 7.55) |
| Characteristics | |
| Spectral type | K0/1 III + A3 V or G4 II + A3+ + (A4) |
| Astrometry | |
| Radial velocity (Rv) | +1.1±0.3 km/s |
| Proper motion (μ) | RA: +20.35 mas/yr Dec.: -6.67 mas/yr |
| Parallax (π) | 6.50±0.88 mas |
| Distance | approx. 500 ly (approx. 150 pc) |
| Absolute magnitude (MV) | 0.1 + 1.4 + 1.5 |
| Details | |
| 12 Aqr Aa/Ab | |
| Mass | 2.6/2.0 M☉ |
| Temperature | 5,012/8,511 K |
| 12 Aqr B | |
| Mass | 1.9 M☉ |
| Temperature | 8,318 K |
| Other designations | |
| 12 Aqr, BD−06°5664, HIP 103981, ADS 14592, CCDM J21041-0549AB, WDS J21041-0549AB | |
| 12 Aqr A: HD 200497, HR 8059, SAO 145065 | |
| 12 Aqr B: HD 200496, HR 8058, SAO 145064 | |
| Database references | |
| SIMBAD | 12 Aqr |
| 12 Aqr A | |
| 12 Aqr B | |
12 Aquarii is a triple star system in the zodiac constellation of Aquarius. 12 Aquarii is the Flamsteed designation. It is visible to the naked eye as a dim star with an apparent visual magnitude of 5.67. Parallax measurements by Hipparcos puts it at a distance of some 500 light-years, or 150 parsecs away. The system is moving further from the Earth with a heliocentric radial velocity of +1.1 km/s.
The magnitude 5.88 primary, component A, is itself a binary star with a separation of 0.05″–0.07″ and an orbital period of around 18.5 yr. The brighter member of this duo is a G-type bright giant with a stellar classification of G4 II and 2.6 times the mass of the Sun. Its companion is an early A-type star with double the mass of the Sun. The tertiary component B is magnitude 7.55 A-type main-sequence star at a separation of 2.44″ from the primary.