The Copernican Revolution spawned the notions that the stars might be suns in their own right and that planetary worlds might orbit such suns. The idea that stars are suns gained plausibility through the investigations by Wollaston and Fraunhofer who showed that the Sun and many stars exhibit similar spectral signatures. It became established scientific fact in 1838 when Bessel, Struve, and Henderson determined, respectively, the distances to 61 Cygni, Vega, and Alpha Centauri, and calculated that they have absolute brightness similar to the Sun. The idea that planets orbit other normal stars remained in the realm of philosophical speculation until 1995, when Michel Mayor and Didier Queloz found, and Geoffrey Marcy and Paul Butler confirmed, the existence of the first planet around a sunlike star, 51 Pegasi. Since that exciting result a decade ago, Marcy and Mayor have led the two most productive and successful research groups searching for extrasolar planets.
Both groups detect extrasolar planets by finding small periodic variations in the radial velocity of the host star. Along with a number of other groups, they worked in relative obscurity for many years, in large part because most astronomers believed that these radial-velocity oscillations would be too small to detect in plausible planetary systems. This belief was based on the analogy with our own solar system, resulting in the theoretical prejudice that massive planets could not form close to their host star, where they would generate the largest reflex motion in the central body.