spacetoday.net: Kepler discovered smallest exoplanet yet around a Sun-like star

Posted: Thu, Feb 21, 2013, 7:32 AM ET (1232 GMT)
Kepler-37b illustration (NASA/Ames/JPL-Caltech)

Astronomers announced Wednesday they have discovered the smallest known extrasolar planet to orbit a Sun-like star, a world only slightly larger than the Moon. The exoplanet, designated Kepler-37b, is one-third the size of the Earth, orbiting a star 210 light0years away. The planet is the smallest of three found around the star: Kepler-37c is slightly smaller than Venus and Kepler-37d is twice the size of the Earth. All three are in orbits closer to their star than Mercury is to the Sun. Astronomers found the planets in data collected by NASA's Kepler mission, which looks for minute, periodic drops in brightness of stars caused by transiting planets.