Kepler-186 is a star located about 500 light-years away in the constellation of Cygnus. It is a K-type dwarf star, which means it is cooler and smaller than our Sun. The star is notable for having a planetary system that includes at least five planets, with Kepler-186f being the most significant as it is the first Earth-sized exoplanet discovered in the habitable zone of its star. Kepler-186f orbits its host star every 130 days and is about 1.1 times the size of Earth. This places it in a region where conditions might allow for liquid water to exist, making it a prime candidate for the search for extraterrestrial life. The discovery of Kepler-186f has provided valuable insights into the diversity of planetary systems in our galaxy.