Didier Queloz

University of Cambridge and ETH Zurich

Research field

Detection of exoplanets by precise radial velocities and transits

As a doctoral student in Geneva, Didier Queloz found the periodic velocity change of the star 51 Pegasi in 1995, and with Michel Mayor showed that a planet of half Jupiter's mass on a four-day orbit causes it. It was the first planet found around a Sun-like star, and the two shared half of the 2019 Nobel Prize in Physics. He is Jacksonian Professor of Natural Philosophy at the Cavendish Laboratory in Cambridge and professor of physics at ETH Zurich. The unit follows his Nobel lecture for the story of the discovery and applies the velocity amplitude formula to his measurement.

In the masterclass

Section 1 derives the radial velocity amplitude and uses it on 51 Pegasi; the spotlight box at the end of that part tells how the measurement was made and defended.

The research is presented in Unit 11: Exoplanets and the Search for Life, in a research spotlight box that explains the result at the level of the unit and links it to the physics you have just learned.

The paper

Nobel Lecture: 51 Pegasi b and the exoplanet revolution