Leon studies the dynamical evolution of planetary systems, with a particular focus on close-in planets subject to strong tidal interactions. Tides can significantly modify star–planet distances, orbital eccentricities, rotation rates, and obliquities of both the star and the planet, thereby reshaping the long-term architecture of planetary systems. He is especially interested in systems locked in mean-motion resonances, where the orbital period ratios of neighboring planets are close to ratios of small integers, similar to the configuration of the three inner Galilean moons of Jupiter.

Leon investigates how tidal dissipation influences these resonant configurations in young planetary systems, accounting for the complex, wave-like tidal response of the host star. To carry out this work, he uses Posidonius, a numerical code developed within the DynaClim group, which enables detailed modeling of tidal and dynamical evolution over long timescales.