Interior structure of Saturn

Abstract

We summarize the principal observational data that constrain interior models of Saturn, and explain why they are relevant. We discuss the behavior of hydrogen, Saturn's major constituent, at pressures on the order of 0.1 to 10 Mbar and temperatures on the order of 10^4 K. Possible behavior and distributions of minor constituents are also considered, along with processes for their transport. We interpret Saturn’s external gravitational and magnetic fields in terms of interior structure, and discuss the relationship between atmospheric zonal flows and the deep interior. The constraint imposed by tidal evolution considerations is evaluated. Calculations for the thermal evolution of Saturn are presented, both with a lid without consideration of possible gravitational unmixing. Possible scenarios for Saturn's mode of origin and their implications for presently observed atmospheric abundances are discussed.