30 Arietis
30 Arietis is a 6th-apparent-magnitude multiple star system in the constellation of Aries. 30 Arietis is the Flamsteed designation. 30 Arietis A and B are separated by, or about at a distance of 145 light-years away. The main components of both systems are both binaries with composite spectra belonging to F-type main-sequence stars, meaning they are fusing hydrogen in their cores. 30 Arietis B also has a second stellar companion, making a total of five stars. The 30 Arietis system is 910 million years old, one fifth the age of the Sun.
Star system
30 Arietis A and B are separated by 38.1", corresponding to 1,700 AU at a distance of 145 light-years. The pair are at almost the same distance, have very similar proper motions, and are considered almost certain to be gravitationally bound with a likely period around 34,000 years. The main components of both systems are both binaries with composite spectra belonging to F-type main-sequence stars, meaning they are fusing hydrogen in their cores.30 Arietis A is a spectroscopic binary with an orbital period of 1.1 days. The primary Aa is an F-type main sequence star about 31% more massive than the Sun, while the companion Ab is a faint red dwarf only about 15% the mass of the Sun.
30 Arietis B has been reported to have a red dwarf companion C at a distance of, and another companion Bb at about. 30 Arietis Bb has a minimum mass consistent with a giant planet, but in 2020, after the orbital inclination was measured, the "planet" was found to fall in the mass range of a red dwarf star. The more distant companion is referred to as C to distinguish it from Bb, and at about 0.5" it has been imaged using adaptive optics.