Stéphane Udry is Professor of Astrophysics at the Department of Astronomy of the University of Geneva. His main field of research is the detection and characterisation of exoplanets. With his team, they have contributed to a large fraction of the detections of the known planets, and in particular they are leading the hunt for terrestrial exoplanets. The team is involved in several instrumentation projects for the detection and characterisation of exoplanets, on the ground and in space, with a special emphasis on small-mass planets and the study of multi-planetary systems in their globality. Coordinating professor of the MOOC "The Diversity of Exoplanets.