Planetary Formation and Evolution Revealed with a Saturn Entry Probe: The Importance of Noble Gases

TL;DR

This paper emphasizes the importance of a Saturn entry probe to measure noble gases and helium in Saturn's atmosphere, which is crucial for understanding giant planet formation, evolution, and the physics of high-pressure H/He mixtures.

Contribution

It highlights the scientific goals and significance of deploying a Saturn entry probe to obtain key atmospheric measurements for planetary science.

Findings

Noble gas abundances will constrain planet formation models.

Helium measurements will reveal phase separation and helium rain.

Comparisons with Jupiter will refine giant planet evolution theories.

Abstract

The determination of Saturn's atmospheric noble gas abundances are critical to understanding the formation and evolution of Saturn, and giant planets in general. These measurements can only be performed with an entry probe. A Saturn probe will address whether enhancement in heavy noble gases, as was found in Jupiter, are a general feature of giant planets, and their ratios will be a powerful constraint on how they form. The helium abundance will show the extent to which helium has phase separated from hydrogen in the planet's deep interior. Jupiter's striking neon depletion may also be tied to its helium depletion, and must be confirmed or refuted in Saturn. Together with Jupiter's measured atmospheric helium abundance, a consistent evolutionary theory for both planets, including "helium rain" will be possible. We will then be able to calibrate the theory of the evolution of all giant planets, including exoplanets. In addition, high pressure H/He mixtures under giant planet conditions are an important area of condensed matter physics that are beyond the realm of experiment.