Constraining Saturn's Core Properties by a Measurement of Its Moment of Inertia - Implications to the Cassini Solstice Mission

TL;DR

Measuring Saturn's pole precession and Lense-Thirring effect during the Cassini Solstice Mission could constrain its internal core properties by determining its axial moment of inertia, revealing insights into its internal structure.

Contribution

Proposes a novel method to constrain Saturn's internal structure by measuring its axial moment of inertia through spacecraft observations during the Cassini Solstice Mission.

Findings

Saturn's moment of inertia can vary by ~2% due to core properties.

A 7-minute change in rotation period affects the moment of inertia estimate.

Measuring angular momentum and rotation period can reveal core characteristics.

Abstract

Knowledge of Saturn's axial moment of inertia can provide valuable information on its internal structure. We suggest that Saturn's angular momentum may be determined by the Solstice Mission (Cassini XXM) by measuring Saturn's pole precession rate and the Lense-Thirring acceleration on the spacecraft, and therefore, put constraints on Saturn's moment of inertia. It is shown that Saturn's moment of inertia can change up to ~2% due to different core properties. However, a determination of Saturn's rotation rate is required to constrain its axial moment of inertia. A change of about seven minutes in rotation period leads to a similar uncertainty in the moment of inertia value as different core properties (mass, radius). A determination of Saturn's angular momentum and rotation period by the Solstice Mission could reveal important information on Saturn's internal structure, in particular, its core properties.