PSJC #85 March 4 2011

Robert French (SETI)

Cupid is Doomed: The Instability of the Inner Uranian Satellites

Uranus is unique in the solar system in having a large number of low-mass satellites close to the planet. We analyzed the orbital stability of these satellites by direct numerical integration and found that the Cupid-Belinda-Perdita subset of satellites is unstable on astronomically short time scales, and that the Cressida-Desdemona-Juliet subset is unstable on slightly longer time scales. Cupid is likely to have a very short existence, eventually impacting Belinda within the next ~100,000 years. We also show that the system is chaotic, and that the variations in Cupid's orbit can be partially attributed to its interactions with the inner Lindblad resonances of Belinda. Finally, we explore the applicability of a power-law relationship that correlates mass assumptions with the time to first orbit crossing.