Thirty years after the discovery of the first exoplanet, astronomers have detected more than 7,000 of them in our galaxy. But there are still billions more to be discovered. At the same time, exoplanetologists have begun to take an interest in their characteristics, with the aim of finding life elsewhere in the universe. This is the background to the discovery of super-Earth HD 20794 d by an international team including the University of Geneva (UNIGE) and the NCCR PlanetS.