2015: Whether the particle size distribution in Saturn’s rings is determined by the history of the rings and details of the particle interaction or is generic for all planetary rings?

Physicists from MSU in collaboration with their colleagues from Univ. of Leicester (UK), Boston Univ. (USA), Univ. of Potsdam (Germany), Kyoto Univ. (Japan), and Univ. of Oulu (Finland) demonstrated that a power-law size distribution with large-size cutoff, as observed in Saturn's rings, is universal for systems where a balance between aggregation and disruptive collisions is steadily sustained.

Although it is well accepted that the particle size distribution in Saturn's rings is not primordial, it remains unclear whether the observed distribution is unique or universal, that is, whether it is determined by the history of the rings and details of the particle interaction or whether the distribution is generic for all planetary rings. We show that a power-law size distribution with large-size cutoff, as observed in Saturn's rings, is universal for systems where a balance between aggregation and disruptive collisions is steadily sustained. Hence, the same size distribution is expected for any ring system where collisions play a role, like the Uranian rings, the recently discovered rings of Chariklo and Chiron, and possibly rings around extrasolar objects.

This work has been published in the paper: N. Brilliantov, P. L. Krapivsky, A. Bodrova, F. Spahnd, H. Hayakawa, V. Stadnichuk, and J. Schmidt, “Size distribution of particles in Saturn's rings from aggregation and fragmentation”, Proc. of the National Academy of Sciences 112(31), 9536-9541 (2015).