EZ Aquarii
EZ Aquarii is a triple star system 11.1 light-years (3.4 parsecs) from the Sun in the constellation Aquarius within the Milky Way. It is also known as Luyten 789-6, Gliese 866 and LHS 68. It is a variable star showing flares as well as smaller brightness changes due to rotation. The aggregate mass of the system is 0.3262±0.0018 solar masses. All three seem to have masses close to the hydrogen burning mass limit.
EZ Aquarii Star System. Credit: SpaceEngine/Bob Trembley | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Aquarius |
| Right ascension | 22h 38m 33.73s |
| Declination | −15° 17′ 57.3″ |
| Apparent magnitude (V) | 12.38 (13.03/13.27/15.07) |
| Characteristics | |
| Spectral type | M5 V |
| B−V color index | +1.96 |
| Variable type | Flare star + BY Dra |
| Astrometry | |
| Radial velocity (Rv) | −59.9 km/s |
| Proper motion (μ) | RA: +2314 mas/yr Dec.: +2295 mas/yr |
| Parallax (π) | 293.6 ± 0.9 mas |
| Distance | 11.11 ± 0.03 ly (3.41 ± 0.01 pc) |
| Absolute magnitude (MV) | 14.75 (15.33/15.58/17.37) |
| Orbit | |
| Primary | EZ Aquarii AC |
| Companion | EZ Aquarii B |
| Period (P) | 2.2506±0.0033 yr |
| Semi-major axis (a) | 0.346±0.004″ |
| Eccentricity (e) | 0.437±0.007 |
| Inclination (i) | 112.4±0.5° |
| Longitude of the node (Ω) | 162.1±0.4° |
| Periastron epoch (T) | 1987.236 ± 0.014 |
| Argument of periastron (ω) (secondary) | −17.7±1.1° |
| Details | |
| EZ Aquarii A | |
| Mass | 0.1187±0.0011 M☉ |
| Radius | 0.175 R☉ |
| Luminosity | 0.00078 L☉ |
| EZ Aquarii C | |
| Mass | 0.0930±0.0008 M☉ |
| Luminosity | 0.00012 L☉ |
| EZ Aquarii B | |
| Mass | 0.1145±0.0012 M☉ |
| Radius | 0.21±0.04 R☉ |
| Temperature | 2650±200 K |
| Other designations | |
| Database references | |
| SIMBAD | data |
EZ Location of EZ Aquarii in the constellation Aquarius | |
The configuration of the inner binary pair may permit a circumbinary planet to orbit near their habitable zone, however no exoplanets have yet been observed. EZ Aquarii is approaching the Solar System and, in about 32,300 years, will be at its minimal distance of about 8.2 ly (2.5 pc) from the Sun. The ChView simulation shows that currently its nearest neighbouring star is Lacaille 9352 at about 4.1 ly (1.3 pc) from EZ Aquarii.