Jupiter's interior from Juno: Equation-of-state uncertainties and dilute core extent

TL;DR

This study uses Juno gravity data and explores equation-of-state uncertainties to model Jupiter's interior, revealing the potential for both extended and small dilute cores, which impacts our understanding of its formation.

Contribution

It assesses the impact of hydrogen-helium equation-of-state uncertainties on Jupiter's interior models using MCMC simulations, revealing diverse core structures.

Findings

Models with dilute cores extending to 20% of Jupiter's mass.

Equation-of-state uncertainties significantly affect interior structure inferences.

Higher internal entropy than Galileo probe measurements suggest.

Abstract

The Juno mission has provided measurements of Jupiter s gravity field with an outstanding level of accuracy, leading to better constraints on the interior of the planet. Improving our knowledge of the internal structure of Jupiter is key to understanding its formation and evolution but is also important in the framework of exoplanet exploration. In this study, we investigated the differences between the state-of-the-art equations of state and their impact on the properties of interior models. Accounting for uncertainty on the hydrogen and helium equation of state, we assessed the span of the interior features of Jupiter. We carried out an extensive exploration of the parameter space and studied a wide range of interior models using Markov chain Monte Carlo (MCMC) simulations. To consider the uncertainty on the equation of state, we allowed for modifications of the equation of state in our calculations. Our models harbour a dilute core and indicate that Jupiter s internal entropy is higher than what is usually assumed from the Galileo probe measurements. We obtain solutions with extended dilute cores, but contrary to other recent interior models of Jupiter, we also obtain models with small dilute cores. The dilute cores in such solutions extend to 20% of Jupiter s mass, leading to better agreement with formation evolution models. We conclude that the equations of state used in Jupiter models have a crucial effect on the inferred structure and composition. Further explorations of the behaviour of hydrogen helium mixtures at the pressure and temperature conditions in Jupiter will help to constrain the interior of the planet, and therefore its origin.