Planetary ring modelling goes full circle

A full planetary ring system has been modelled for the first time using realistic particle sizes and interactions.

Chariklo, a minor planet or ‘centaur’ that orbits between Jupiter and Neptune, is the smallest known body in our Solar System to have rings. A team that included researchers from the University of Tsukuba used a supercomputer to calculate the motions of 345 million particles in Chariklo’s two rings. They set particle size to a few meters, and accounted for collisions and gravitational attraction. The results suggest that the ring particles are half as dense as Chariklo itself, which, according to some theories, would cause gravitational disturbances in the inner ring that should break up the rings within 100 years.

The group speculates that the rings endure owing to either much smaller sized particles than they had assumed for the model, or the presence of a ‘shepherd moon’ — an orbiting object whose gravitational effect herds the ring particles — and will investigate such theories in their next model.