Kepler-186f

Kepler-186f (also known by its Kepler object of interest designation KOI-571.05) is a candidate Earth-sized exoplanet orbiting within the habitable zone of the red dwarf star Kepler-186, the outermost of five planets discovered around the star by NASA's Kepler space telescope. It is located about 580 light-years (180 parsecs) from Earth in the constellation of Cygnus. Kepler-186f orbits its star at a distance of about 0.43 AU (64,000,000 km; 40,000,000 mi) from its host star with an orbital period of roughly 130 days, and a radius around 1.17 times that of Earth. As one of the more promising candidates for habitability, it was the first planet with a radius similar to Earth's to be discovered in the habitable zone of another star. However, key components still need to be found to determine its habitability for life, including an atmosphere, and its composition and if liquid water can exist on its surface.