Our Sun has many neighbors, but the closest star system to the Sun is Alpha Centauri. We see Alpha Centauri as a single star on our Sky, but it is expected to be a system of three stars. It means Alpha Centauri is possibly made of three stars.
The system is made of two major stars and a small and faint red dwarf. The two main stars are Alpha-Centauri A and Alpha-Centauri B. Alpha-Centauri A is a bigger star than that of our Sun. It is almost 110% of the Sun’s mass and almost 120% of the Sun’s luminosity. Alpha-Centauri B is, however, smaller than the Sun. It is only 90.7% of the Sun’s mass and only 44.5% of the Sun’s visual luminosity.
The third star in the Alpha Centauri system is a red dwarf, which is known as Proxima Centauri. Proxima is expected to be the closest star to our Solar System. This red dwarf is believed to be about 4.22 light years away from the Sun. Our sun is almost five hundred times brighter than Proxima. Until 1915, Proxima was unaware to the world. Before 1915, Alpha Centauri was believed as a tightly orbiting pair.
Alpha-Centauri A is the fourth biggest star visible from Earth. Alpha Centauri System is a brightest star in the southern hemisphere of Earth but it is almost invisible in the northern hemisphere. In 2012, scientists discovered a planet orbiting around Alpha-Centauri B, by using a special instrument called the High Accuracy Radial velocity Planet Searcher.