Centauri

Centauri is the designation commonly used for the Alpha Centauri star system, the closest known stellar system to the Sun. Located in the southern constellation Centaurus, the system lies about 4.37 light-years from the Sun, with the primary pair, Alpha Centauri A and Alpha Centauri B, and a distant companion, Proxima Centauri, in gravitational association.

The system consists of three stars. Alpha Centauri A (spectral type G2V) and Alpha Centauri B (type K1V) form a bound binary, orbiting their common center of mass approximately every 79 to 80 years at a separation that ranges around 23 astronomical units. Alpha Centauri A is slightly brighter and more massive than the Sun, while Alpha Centauri B is smaller and cooler. Proxima Centauri is a red dwarf (type M5.5Ve) and, at a wide separation, is the closest known star to the Sun, about 0.21 parsecs (roughly 0.7 light-years) from the AB pair. The three stars constitute a wide, hierarchical triple system, with Proxima's orbit around the AB pair remaining a subject of ongoing study.

Proxima Centauri hosts at least one confirmed exoplanet, Proxima Centauri b, detected by radial-velocity measurements. It has an Earth-mass minimum and orbits very close to its star, with a period of about 11.2 days, in the star’s habitable zone. The system remains a focal point for studies of nearby exoplanets and for proposals concerning interstellar exploration, given its proximity and accessibility for future observations.