Prometheus (moon)

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Prometheus Template:IPAc-en is an inner satellite of Saturn. It was discovered on 24 October 1980 from images taken by the Voyager 1 probe, and was provisionally designated Template:Nowrap.Template:Sfn

In late 1985 it was officially named after Prometheus, a Titan in Greek mythology.Template:Sfn It is also designated Template:Nowrap.Template:Sfn

Prometheus is extremely elongated, measuring approximately Template:Convert. It has several ridges and valleys and a number of impact craters of about Template:Convert diameter are visible, but it is less cratered than nearby Pandora, Epimetheus, and Janus. From its very low density and relatively high albedo, it is likely that Prometheus is a very porous icy body. There is much uncertainty in these values, however, and so this remains to be confirmed.

Interactions with F Ring and other moons

Prometheus is a shepherd satellite for the inner edge of Saturn's narrow F Ring. Pandora orbits just outside the F Ring, and has traditionally been viewed as an outer shepherd of the ring; however, recent studies indicate that only Prometheus contributes to the confinement of the ring.<ref name = "LakdawallaE2014">Template:Cite web</ref><ref name="Cuzzi2014">Template:Cite journal</ref>

Images from the Cassini probe show that Prometheus's gravitational influence creates kinks and knots in the F Ring as it shepherds material from it. The orbit of Prometheus appears to be chaotic, due to a series of four 121:118 mean-motion resonances with Pandora.Template:Sfn The most appreciable changes in their orbits occur approximately every 6.2 years,Template:Sfn when the periapsis of Pandora lines up with the apoapsis of Prometheus, as they approach to within approximately 1400 km. Prometheus is itself a significant perturber of Atlas, with which it is in a 53:54 mean-longitude resonance.Template:Sfn

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