Uranus has 13 small stallites orbiting closer to the planet than Miranda. Some of these moons move on tightly packed orbits, and previous dynamical studies (e.g. Duncan and Lissauer 1997, French and Showalter 2012) found that the inner Uranian system is unstable, with some orbits crossing in well under 1 Myr. This instability contradicts the usual assumption that the system will evolve into a more stable state over the age of the Solar System. Here we revisit the question of of the stability of Uranian inner moons with a different approach from previous works. Instead of using nominal orbits and studying the resulting dynamics, we vary orbital elements of the moons within the range allowed by observations, and look for potential stable solutions. We find that the 44:43 MMR between Belinda and Perdita is a major source of chaos, and is very sensitive to initial conditions. We tentatively find a stable configuration in this resonance, which appears to stabilize the Cupid-Belinda-Perdita trio. At the meeting we will present resuilts for a larger number of moons, and discuss if a long term (Gyr-scale?) stability of the inner Uranian system is possible.
AAS/Division of Dynamical Astronomy Meeting
- Pub Date:
- August 2020