The Interior of Saturn

TL;DR

This paper reviews current knowledge of Saturn's interior structure and thermal evolution, highlighting recent advances, ongoing uncertainties, and prospects for future insights from Cassini data.

Contribution

It synthesizes recent observational and theoretical developments, emphasizing the role of new methods and data in constraining Saturn's interior models.

Findings

Progress in understanding physical inputs like equations of state and gravity field.

Identification of modeling uncertainties and degeneracies.

Potential for future insights from Cassini's Grand Finale data.

Abstract

We review our current understanding of the interior structure and thermal evolution of Saturn, with a focus on recent results in the Cassini era. There has been important progress in understanding physical inputs, including equations of state of planetary materials and their mixtures, physical parameters like the gravity field and rotation rate, and constraints on Saturnian free oscillations. At the same time, new methods of calculation, including work on the gravity field of rotating fluid bodies, and the role of interior composition gradients, should help to better constrain the state of Saturn's interior, now and earlier in its history. However, a better appreciation of modeling uncertainties and degeneracies, along with a greater exploration of modeling phase space, still leave great uncertainties in our understanding of Saturn's interior. Further analysis of Cassini data sets, as well as precise gravity field measurements from the Cassini Grand Finale orbits, will further revolutionize our understanding of Saturn's interior over the next few years.