The Shaw Prize in Astronomy for 2015 is awarded to William J Borucki for his conception and leadership of the Kepler Mission, which has greatly advanced knowledge of both extrasolar planetary systems and stellar interiors. He is the Principal Investigator of the Kepler Mission, NASA’s Ames Research Center.
In 1984, William J Borucki and Audrey Summers published a paper assessing the potential for detecting extrasolar planetary systems by transit photometry. The key concept is to simultaneously monitor the brightness of a large number of stars. Planets are revealed by the dips in brightness they produce when they pass in front of (transit) their host stars. Successive transits by a planet are spaced by its orbit period, which helps to distinguish transits from other sources of stellar variability. Transit depths determine the ratio of the planet’s surface area to that of its host star. William J Borucki and Audrey Summers emphasized that detection of Earth-size planets would require observations from above the atmosphere.