Kepler-186

Kepler-186 is a main-sequence M1-type dwarf star, located 177.5 parsecs (579 light years) away in the constellation of Cygnus. The star is slightly cooler than the sun, with roughly half its metallicity. It is known to have five planets, including the first Earth-sized world discovered in the habitable zone: Kepler-186f. The star hosts four other planets discovered so far, though they all orbit interior to the habitable zone.

Within two first years of gathered data, the signals of four inner planetary candidates were found. Discussion of planets in the system was taking place in August and November 2013. In February 2014, those planets were confirmed through the "verification by multiplicity" method. The fifth outermost candidate was confirmed in the same manner in April 2014. The possibility that the signals in the light curve of the star were actually from something else has been ruled out by an investigation with the W. M. Keck and Gemini Observatories, using speckle imaging and adaptive optics techniques, which, while unable to resolve the planets, were able to rule out other possibilities than the system of planets.