"Here we show that irregular satellites are captured in a thin spatial region where orbits are chaotic , and that the resulting orbit is either prograde or retr

"Here we show that irregular satellites are captured in a thin spatial region where orbits are chaotic , and that the resulting orbit is either prograde or retrograde depending on the initial energy. Dissipation then switches these long-lived chaotic orbits into nearby regular (non-chaotic) zones from which escape is impossible. The chaotic layer therefore dictates the final inclinations of the captured moons" http://sci-hub.tw/10.1038/nature01622 http://sci-hub.tw/10.1038/nature01622