Proxima Centauri b exoplanet, illustration. Proxima Centauri (upper left) is the closest star to the Sun. It lies 4.25 light years from Earth in the constellation Centaurus. Proxima Centauri b is a planet that orbits in the habitable zone around Proxima Centauri, where the temperature may be suitable for liquid water to exist on its surface. The first signs of Proxima Centauri b were seen in 2013, but its presence wasnt confirmed until 24 August 2016.Ramon Andrade 3DcienciaScience Photo Library