Proxima Centauri b

Proxima Centauri b is an exoplanet orbiting within the habitable zone of the red dwarf star Proxima Centauri in the constellation Centaurus. It can also be referred to as Proxima b, or Alpha Centauri Cb. The host star is the closest star to the Sun, at a distance of about 4.2 light-years (1.3 parsecs) from Earth, and is part of the larger triple star system Alpha Centauri. Proxima b and Proxima d, along with the currently disputed Proxima c, are the closest known exoplanets to the Solar System.

Proxima Centauri had become a target for exoplanet searches already before the discovery of Proxima Centauri b, but initial studies in 2008 and 2009 ruled out the existence of larger-than-Earth exoplanets in the habitable zone. Planets are very common around dwarf stars, with on average 1–2 planets per star, and about 20–40% of all red dwarfs have one in the habitable zone. Additionally, red dwarfs are by far the most common type of stars.