Contributions > By speaker > Poon Michael

This decade has seen the first measurements of planetary obliquities – the tilt between a planet's rotational and orbital axes – for directly-imaged super-Jupiters, enabling new constraints on their formation and evolutionary pathways. With only four measurements to date, we develop a hierarchical Bayesian framework to extract population-level constraints and test whether super-Jupiters form like scaled-up planets or scaled-down stars. Using a single-parameter Fisher distribution, we compare two models: a brown dwarf-like formation scenario predicting isotropic obliquities, versus a planet-like formation scenario favouring obliquities concentrated near 20 − 30 degrees, as in our Solar System. Among the four young super-Jupiters with measured obliquities, we find evidence favouring brown dwarf-like formation. These preliminary results suggest that super-Jupiters may form through fundamentally different processes than Solar System planets, motivating further observations to strengthen this emerging population-level inference.