Michel Gustave Édouard Mayor (born 12 January 1942) is a noted Swiss astrophysicist whose research has shaped modern planet hunting. He served for many years at the University of Geneva and is professor emeritus of the university's Department of Astronomy. After formal retirement he continued active research at the Geneva Observatory and remained central to projects that refined precision radial-velocity techniques for detecting planets.
Career, methods and instruments
Mayor trained and worked as an observational astronomer, focusing on high-precision spectroscopy. His group advanced the radial velocity method, which detects tiny motions of a star induced by an orbiting planet. The team developed and used dedicated spectrographs, notably the ELODIE instrument that made the breakthrough detection in 1995 and later influenced the design of the even more precise HARPS spectrograph employed in many subsequent discoveries. These instruments measure shifts in stellar spectral lines with great accuracy and helped open the field of exoplanet characterization.
Discovery of 51 Pegasi b
In 1995 Mayor and his collaborator Didier Queloz announced the detection of 51 Pegasi b, the first planet found orbiting a solar-type star. The object was identified by its strong radial-velocity signal and stood out because it was a close-in gas giant — a type later called a "hot Jupiter." The finding demonstrated that planets exist in configurations very different from our own Solar System and it triggered a rapid expansion of observational and theoretical work on extrasolar systems.
Significance and legacy
The discovery marked the beginning of a new era in astronomy: extensive surveys of other stars, the development of refined detection methods (radial velocity, transits, direct imaging), and a large and growing catalog of exoplanets of many types. Mayor's work gave observational proof that planetary systems are common and diverse. The 1995 result is often contrasted with earlier detections of planets around pulsars; 51 Pegasi b was notable because it orbited a star similar to the Sun.
Awards and recognition
- Co-recipient with Didier Queloz of the 2019 Nobel Prize in Physics for the discovery of an exoplanet orbiting a solar-type star.
- Recipient of other major honors including the 2010 Viktor Ambartsumian International Prize and the 2015 Kyoto Prize, reflecting long-term influence on astrophysics.
Context and notable facts
51 Pegasi b orbits the star 51 Pegasi, a sun-like main-sequence star; its detection shifted expectations about planetary formation and migration. Mayor's career illustrates how improved instrumentation and patient, careful measurement can yield paradigm-changing discoveries. His group at Geneva remains a central hub for exoplanet surveys and instrumental innovation, and his work continues to be cited in studies of planetary demographics and formation theory.