EZ Aquarii is a triple star system 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.
William E. Kunkel announced that Luyten 789-6 was a flare star in 1972, after having observed seven flares. It was given its variable star designation, EZ Aquarii, in 1978.
System
All three components are M-type red dwarfs. The pair EZ Aquarii AC form a spectroscopic binary with a 3.8-day orbit and a 0.03 AU separation. This pair share an orbit with EZ Aquarii B that has an 823-day period. The A and B components of Luyten 789-6 together emit X-rays.
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 from the Sun. The ChView simulation shows that currently its nearest neighbouring star is Lacaille 9352 at about from EZ Aquarii.
EZ Aquarii A The brighter resolved star is a spectroscopic binary consisting of two red dwarfs. They orbit every days with an eccentricity of 0 (ie. circular).
The primary, component Aa or just A, is of type M5V and has a mass of solar masses. It has an absolute magnitude at wavelengths centered at 5500 Angstroms of 15.33 making it the brightest of the three. Some alternate designations for it are EZ Aqr, GL 866A, L 789-6 A and LHS 68.
The secondary, component Ab, is likely a type MV red dwarf with a mass of solar masses. It is the dimmest of the three star with an absolute magnitude of 17.37. An alternate designation for it is GL 866C.
EZ Aquarii B There is less known about this star compared to A. Its type is likely MV with a mass of solar masses. It orbits the spectroscopic pair with a period of at an eccentricity of . It has an absolute magnitude of 15.58. Some alternate designations for it are GL 866B and L 789-6 B.
Other details The high proper motion of EZ Aquarii may have been discovered by Willem Jacob Luyten with his automated photographic plate scanner.
See also List of nearest stars and brown dwarfs
Notes
References
External links Image EZ Aquarii Solstation provides an orbital animation as well as a visualization of the habitable zone around EZ Aquarii B.