都卜勒光譜學
Robert Paul Butler (born 1960) is an astronomer who searches for extrasolar planets. he and his team have discovered over half of the planets found orbiting nearby stars. He is also noted for his pioneering work in Doppler spectroscopy, a method used to detect stars having orbiting planets by measuring the "wobble" induced by the gravitational forces between the star and its orbiting planet(s).