29 Aquarii
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Aquarius |
| Right ascension | 22h 02m 26.24845s |
| Declination | −16° 57′ 53.3959″ |
| Apparent magnitude (V) | 6.39 |
| Characteristics | |
| Spectral type | A2 V + K0 III |
| B−V color index | 0.447±0.022 |
| Astrometry | |
| Radial velocity (Rv) | +15.0±4.3 km/s |
| Proper motion (μ) | RA: +5.292 mas/yr Dec.: +1.256 mas/yr |
| Parallax (π) | 5.5489±0.1285 mas |
| Distance | 590 ± 10 ly (180 ± 4 pc) |
| Orbit | |
| Period (P) | 0.945 d |
| Eccentricity (e) | 0.00 |
| Periastron epoch (T) | 2,436,814.418±1.0 JD |
| Semi-amplitude (K1) (primary) | 97.9 km/s |
| Other designations | |
| BD−17°6422, HD 209278, HIP 108797, HR 8396, SAO 164830, WDS J22024-1658 | |
| Database references | |
| SIMBAD | data |
29 Aquarii is a binary star system located around 590 light years away from the Sun in the equatorial constellation of Aquarius. 29 Aquarii is the Flamsteed designation; the system also bears the variable star designation DX Aquarii. It is a challenge to view with the naked eye, appearing as a dim star with a combined apparent visual magnitude of 6.39. The system is moving further from the Earth with a heliocentric radial velocity of about +15 km/s.
This is a spectroscopic binary system with a close circular orbit taking just 0.945 days to complete. Despite their proximity, this does not appear to be a contact binary system. The orbital plane of the two stars lies near the line of sight, so they form an Algol-type eclipsing binary. The first component of the system is an A-type main sequence star with a stellar classification of A2 V. Its companion is giant star with a classification of K0 III.
The variability of this system was first noticed in 1965 by W. Strohmeier of Remeis-Observatory in Bamberg, Germany. He later discovered that the variability was caused by a binary companion eclipsing the primary star.