The origin of rings is one of the final arguments in a series explaining solar system formation. Liquid moons placed in circular orbits close to the planet (inside the Roche limit) will deposit ring material as they migrate. Once outside the limit, moons retain this material. Finally, the shape of the moon, Pan, is explained, using the same mechanism that forms rings.
References
[1]
Charnoz, S., Canup, R.M., Crida, A. and Dones, L. (2017) The Origin of Planetary Ring Systems. https://arxiv.org/pdf/1703.09741
[2]
Fitzpatrick, R. (2016) Roche Ellipsoids. https://farside.ph.utexas.edu/teaching/336L/Fluid/node37.html
[3]
Thomas, P.C. and Helfenstein, P. (2020) The Small Inner Satellites of Saturn: Shapes, Structures and Some Implications. Icarus, 344, Article ID: 113355. https://doi.org/10.1016/j.icarus.2019.06.016
[4]
Thomas, P.C. (2010) Sizes, Shapes, and Derived Properties of the Saturnian Satellites after the Cassini Nominal Mission. Icarus, 208, 395-401. https://doi.org/10.1016/j.icarus.2010.01.025
