The two innermost planets are about 60 to 90 times closer to their star than the Earth to the sun, with orbits only 1.5 and 2.4 days long, respectively.

TRAPPIST-1 is a type of star known as an ultracool dwarf that is very common in the Milky Way, making up about 15 percent of the stars near the sun. TRAPPIST-1 is 2,000 times less bright than the sun, a bit less than half as warm as the sun, about one-twelfth the sun's mass, and less than one-eighth the sun's width, making it only slightly larger in diameter than Jupiter. In comparison, Alpha Centauri, the nearest star system, is about 4.3 light-years from Earth. This dim cold red star, now known as TRAPPIST-1, is located in the constellation of Aquarius about 39 light-years from Earth.

'These kinds of tiny, cold stars may be the places we should first look for life elsewhere in the universe, because they may be the only places where we can detect life on distant Earth-sized planets with our current technology,' study lead author MichaГ«l Gillon, an astronomer at the University of LiГЁge in Belgium, told .ДЄstronomers focused on a star originally named 2MASS J23062928-0502285 that was discovered using TRAPPIST (TRAnsiting Planets and PlanetesImals Small Telescope), a telescope in Chile. Three potentially habitable Earth-size planets have been discovered orbiting a dim, cold nearby star that is barely larger than Jupiter, researchers say.

Alien on tiny planet