30 Arietis

30 Arietis (abbreviated 30 Ari) 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 $136.862$ or about $−15.188$ at a distance of 130 light years away. The main components of both systems are both binaries with a composite spectra belonging to F-type main-sequence stars, meaning they are fusing hydrogen in their cores. 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 1,500 AU at a distance of 130 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 a 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 at a distance of $141.411$ and another red dwarf Bb at about $−10.677$. In 2020, after the inclination of the planetary orbit was measured, the "planet" was found to fall in the mass range of a brown or red dwarf. The more distant companion was referred to as C to distinguish it from Bb, and at about 0.5" it has been imaged using adaptive optics.

30 Arietis Bb
30 Arietis Bb (sometimes abbreviated 30 Ari Bb) is a red dwarf which orbits the F-type main sequence star 30 Arietis Ba, located in a quintuple star system approximately 146 light years away in the constellation Aries. The red dwarf, initially believed to be a massive planet or brown dwarf, was announced in a paper published online on September 24, 2009. It was discovered by using precision radial velocity measurements from the echelle spectrograph installed on the Alfred-Jensch telescope in Karl Schwarzschild Observatory. The star had a minimum mass of nearly 10 times that of Jupiter. In 2020, after the inclination of the planetary orbit was measured to be just 4.14$4.14$°, the "planet" was found to fall in the mass range of red dwarf stars.