She’s 490 light-years from Earth but we call her our planet’s cousin; Kepler 186f is an exo-planet orbiting the red dwarf Kepler-186. It is the first planet with a radius similar to Earth’s to be discovered in the habitable zone of another star. NASA’s Kepler spacecraft detected it using the transit method, along with four additional planets orbiting much closer to the star (all modestly larger than Earth). Analysis of three years of data was required to find its signal. The results were presented initially at a conference on 19 March 2014 and some details were reported in the media at the time.The full public announcement was on 17 April 2014, followed by publication in Science.
Kepler-186f is the first Earth-size alien planet found in the habitable zone of its star. That means the planet, which is only slightly larger than Earth, is in the part of its star system where liquid water could exist on the planet’s surface. Astronomers have found other planets in the habitable zones of their stars, but this is the first time a planet this close in size to Earth has ever been found in the habitable zone of its star. This is the best case for a habitable planet yet found. Because of Kepler-186’s location in the habitable zone around its star, the planet might be a place where life can thrive. It’s possible that the planet has an atmosphere that can help keep water in liquid form on the surface, a prerequisite for life as it is known on Earth. Kepler-186f is on the outer edge of the habitable zone, so it is possible that the planet’s water could freeze. Its larger size, however, could mean the planet has a thicker atmosphere, insulating the planet, San Francisco State University astronomer and study co-author Stephen Kane said in a statement.
Although they know the alien world is in its star’s habitable zone, scientists still aren’t sure what the planet’s atmosphere consists of, and they cannot say with certainty that Kepler-186f could support life. The planet is Earth-sized, but it might not be Earth-like. The newly discovered exoplanet orbits about 32.5 million miles (52.4 million kilometers) from its sun. It takes Kepler-186f about 130 days to orbit its red dwarf star. Scientists have described Kepler-186f as a cousin to Earth. The Kepler-186 star is dimmer than the sun, so the planet may be somewhat similar to Earth in size, but its star is not the same as the sun. The Kepler-186 star is about half the mass of the sun, and the newly discovered planet is far enough away from its star that powerful flares may not greatly affect the planet, scientists have said.