EZ Aquarii

EZ Aquarii is a triple star system 11.1 ly 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.

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 from the Sun. The ChView simulation shows that currently its nearest neighbouring star is Lacaille 9352 at about 4.1 ly from EZ Aquarii.

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.

EZ Aquarii A
This star is a red dwarf of type M5V which has a mass of $2.251$ solar masses. It has a parallax of $0.346$. Its period in days around EZ Aquarii C is $0.437$ with an eccentricity of 0 which together make up the primary of the system. 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.

EZ Aquarii B
There is less known about this star compared to A. Its type is likely a type MV with a mass of $112.4$ solar masses. It orbits the AC system with a period of $162.1$ at an eccentricity of $-17.7$. It has an absolute magnitude of 15.58, making it dimmer than A but brighter than C. Some alternate designations for it are GL 866B and L 789-6 B.

EZ Aquarii C
Like the other two, this star is likely a type MV with a mass of $0.119$ solar masses. It orbits A in a period of $0.093$ with a nearly circular orbit. It is the dimmest of the three with an absolute magnitude of 17.37. An alternate designation for it is GL 866C.

Other details
The high proper motion of EZ Aquarii may have been discovered by Willem Jacob Luyten with his automated photographic plate scanner.