Didier Queloz
Swiss astronomer who co-discovered the first exoplanet around a Sun-like star.
Didier Queloz is a Swiss astronomer who, alongside Michel Mayor, made the landmark 1995 discovery of 51 Pegasi b, the first planet found orbiting a Sun-like star. This detection, achieved by measuring tiny periodic shifts in the star’s radial velocity using a new spectrograph called ELODIE, identified a type of giant planet now known as a Hot Jupiter. The breakthrough launched the field of exoplanet research and earned Queloz, Mayor, and Jim Peebles the 2019 Nobel Prize in Physics. Born in Switzerland in 1966, Queloz earned his MSc, DEA, and PhD at the University of Geneva, where Mayor served as his doctoral advisor. He is the Jacksonian Professor of Natural Philosophy at the University of Cambridge, a fellow of Trinity College, Cambridge, and a professor of physics at ETH Zurich, where he also became founding director of the Center for the Origin and Prevalence of Life in 2022. Early in his career, Queloz developed methods to distinguish planetary signals from stellar activity, creating algorithms that became standard in Doppler spectroscopy. He led the installation of the CORALIE spectrograph and later contributed to the HARPS instrument, which enabled detections of smaller exoplanets. His research on transiting planets, including the first spectroscopic transit detection using the Rossiter-McLaughlin effect, revealed that many exoplanets have misaligned or retrograde orbits, offering new insights into planetary formation. He received the 2011 BBVA Foundation Frontiers of Knowledge Award and the 2017 Wolf Prize in Physics for his work.
- field
- Astronomy, Astrophysics
- nationality
- Swiss
- known_for
- Discovery of 51 Pegasi b, the first exoplanet orbiting a Sun-like star
Lore & Background
Queloz's career focused on expanding detection and measurement capabilities for exoplanets. He identified stellar activity as a limitation for planet detection and published a reference paper on disentangling stellar activity from planetary signals. He also pioneered the combination of transit and Doppler spectroscopy to measure planetary bulk densities, and led spectroscopic follow-up for the WASP consortium and CoRoT space mission.
Reader's Guide
Didier Queloz's significance lies in his role at the origin of the exoplanet revolution. This achievement earned them half of the 2019 Nobel Prize in Physics. Beyond this discovery, Queloz made lasting contributions to the technical foundations of exoplanet science. He developed methods to separate stellar activity from planetary signals, created new spectrographs and detection algorithms, and established statistical metrics for analyzing noise in transit data. His work on transiting planets revealed that many hot Jupiters have misaligned or retrograde orbits, providing new insights into planet formation. He also led the spectroscopic follow-up that confirmed the first rocky exoplanet, COROT-7b, and Earth-like densities for Kepler-10.
Did You Know?
- The discovery of 51 Pegasi b was made using the ELODIE spectrograph at the Haute-Provence Observatory.
- Queloz led the installation of the CORALIE spectrograph on the Swiss 1.2-metre Leonhard Euler Telescope.
- He served as project scientist for the HARPS spectrograph, a key instrument for exoplanet radial velocity measurements.
- In 2022, he became founding director of the Center for the Origin and Prevalence of Life at ETH Zurich.
Frequently Asked Questions
Who is Didier Queloz?
He is a Swiss astronomer born on 23 February 1966, best known for identifying the first planet confirmed to circle a star like our Sun. He splits his academic work between the University of Cambridge and ETH Zurich.
What is Didier Queloz most famous for?
In 1995, working alongside Michel Mayor, he detected 51 Pegasi b, the first exoplanet found orbiting a Sun-like star. That single detection essentially gave birth to the modern field of exoplanet science.
Did Didier Queloz win a Nobel Prize?
Yes, he shared the 2019 Nobel Prize in Physics with Michel Mayor for their 1995 discovery. The committee cited how their finding proved that planets could exist around ordinary stars and opened an entirely new area of research.
Where does Didier Queloz teach and work?
He holds the Jacksonian Professorship of Natural Philosophy at the University of Cambridge and is a fellow of Trinity College. He simultaneously maintains a professorship in physics at ETH Zurich in Switzerland.
Why is Didier Queloz's discovery considered so important?
Before 1995, no one had confirmed a planet around a star comparable to the Sun, so the exoplanet field barely existed as a discipline. His work with Mayor demonstrated that such worlds were detectable, which triggered decades of follow-up research and the identification of thousands of additional planets.
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