HIP 45734 is a quadruple system of 2+2 architecture located at 68 pc from the Sun .
The outer 9″ system A , B has a period of \sim 10 ^ { 4 } yr .
The subsystem Aa , Ab is a visual binary with a period of 20.1 years and an eccentricity of 0.78 .
Its periastron in 2019.1 was observed spectroscopically , yielding masses ( 1.10 \pm 0.04 and 0.98 \pm 0.03 { \cal M } _ { \odot } ) and orbital parallax , 14.90 \pm 0.37 mas .
The masses , luminosities , and colors approximately agree with evolutionary models of main sequence stars .
The component Aa has a detectable lithium line , whereas in Ab it is absent .
The pair Ba , Bb is a single-lined spectroscopic binary with a period of 0.55552 day and an orbital inclination of \sim 45° derived by modeling the rotationally broadened line profile with “ flat bottom ” .
The mass of Bb is \sim 0.4 { \cal M } _ { \odot } .
The star B is chromospherically active ( an x-ray source ) ; its flux is modulated with the orbital period by starspots , in addition to occasional flares .
The system is probably older than \sim 600 Myr ; it does not belong to any known moving group .