Proxima Centauri has two confirmed exoplanets: Proxima Centauri b and Proxima Centauri c. Proxima Centauri b orbits the star at a distance of roughly with an orbital period of approximately 11.2 Earth days. Its estimated mass is at least 1.17 times that of Earth. Proxima b is orbiting within Proxima Centauri's habitable zone—the range where temperatures are right for liquid water to exist on its surface—but because Proxima Centauri is a red dwarf and a flare star, its habitability is disputed. A super-Earth, Proxima Centauri c, orbits roughly away every . A faint additional signal was detected in a 2019 exoplanet search using radial velocity data, with a period of 5.15 days. Possible explanations for the signal include undiscovered exoplanets or statistical noise.