Comparing Jupiter interior structure models to Juno gravity measurements and the role of a dilute core

TL;DR

This paper compares Jupiter interior models with Juno gravity data, highlighting the importance of a dilute core and heavy element enrichment, and discusses challenges in modeling Jupiter's structure accurately.

Contribution

It introduces interior models based on ab initio simulations that incorporate a dilute core to better match gravity measurements and explores the implications for Jupiter's composition.

Findings

Dilute core models improve fit to Juno gravity data.

Deep metallic envelope is enriched in heavy elements.

Core mass estimated at 7-25 Earth masses.

Abstract

The Juno spacecraft has measured Jupiter's low-order, even gravitational moments, $J_2$--$J_8$, to an unprecedented precision, providing important constraints on the density profile and core mass of the planet. Here we report on a selection of interior models based on ab initio computer simulations of hydrogen-helium mixtures. We demonstrate that a dilute core, expanded to a significant fraction of the planet's radius, is helpful in reconciling the calculated $J_n$ with Juno's observations. Although model predictions are strongly affected by the chosen equation of state, the prediction of an enrichment of $Z$ in the deep, metallic envelope over that in the shallow, molecular envelope holds. We estimate Jupiter's core to contain an 7--25 Earth mass of heavy elements. We discuss the current difficulties in reconciling measured $J_n$ with the equations of state, and with theory for formation and evolution of the planet.