Presentation #110.09 in the session Many Planets, More Rings Posters (Poster + Lightning Talk)
We present updated estimates for both the age and fractional pollution of Saturn’s rings. Our updated Markov-chain based model for the bombardment of Saturn’s rings, which takes into account recent work by Kempf et al. 2023 which provides upper and lower bounds on the exogenous meteoritic mass flux impacting the ring system, changes our previous estimate by about an order of magnitude.
Our simulation calculates the fractional pollution of the rings over time, taking into account particle size distributions at different ring radii, for each major ring region. The stochastic Markov-chain approach allows us to simulate the accumulation of an icy-regolith layer on the surfaces of ring particles and calculate the most probable average regolith depth for a typical ring particle over time. This layer, composed of broken up icy material and meteoritic material, will increase in both depth and fractional pollution over time, giving us a view into the history of the composition of the ring system.
An analysis of the FUV spectra of Saturn’s rings as measured by Cassini UVIS is performed to retrieve the current composition of the rings. This is accomplished through spectral modeling using Hapke’s model for bidirectional reflectance, and a non-linear least squares fit analysis comparing model spectra to observed UVIS spectra. In order to reduce the number of free parameters in the fit, we constrain the surface roughness of the ring particles through an analysis of the FUV phase curves of the rings at each major ring region (A, B and C). By comparing the spectral analysis with the bombardment simulation, we work backwards through time to estimate the age of Saturn’s rings.