Hunting for Sub-Moons: A Map of Stability in the Jovian and Kronian Systems

The existence or inexistence of subsatellites (satellites of satellites) in the Solar System has never been demonstrated. Kollmeier and Raymond (2019) showed from an analytical approach exclusively based on tides that Jupiter and Saturn could both potentially host subsatellites. Later, Sucerquia, Mario et al. (2024) studied the stability of equatorial rings around main satellites of the gaseous planets, through N-body simulations. They concluded that such rings could be stable over long timescales, in contrast with the absence of direct observations. We extend this work by examining the stability of sub-moons around a large number of Jupiter’s and Saturn’s satellites—including the irregulars. Using N-body simulations that account for gravitational perturbations from the Sun and the neighbour planet, we evaluate the survival rates of subsatellites. We produce a map of the best candidates capable of hosting sub-satellites in the Jovian and Kronian systems.