Kepler Mission Overview and Planet Discoveries

The first step in discovering the extent of life in our galaxy is to determine the number of terrestrial planets in the habitable zone (HZ) of solar-like stars. Recent discoveries based on the Doppler-velocity technique have shown that many stars have giant planets, but this technique is not effective for the search for Earth-size planets orbiting solar-like stars. The Kepler Mission is based on observing transits and is designed specifically to determine the frequency of terrestrial planets in the HZ. It was launched on March 6, 2009 and is now monitoring the brightness of 150,000 solar-like stars to detect patterns of transits that provide the size of the planet relative to the star and its orbital period. Combining these measurements with ground-based spectroscopy fixes the stellar parameters, the planet radius, orbital distance, and location relative to the HZ.

Current Kepler observations show the presence of over 800 candidate planets, 1800 eclipsing binary stars, and variable stars of amazing variety. Many of the planetary candidates are smaller than Neptune. Candidates as small as Earth in short period orbits are being detected. Discoveries of seven exoplanets are shown including one of with two confirmed transiting planets and a third companion. The candidates and the announced planets are compared with known exoplanets with respect to mass, size, density, and orbital period.