Understanding Jupiter's interior

Militzer, Burkhard; Soubiran, François; Wahl, S. M.; Hubbard, W. B.

doi:10.1002/2016je005080

Cited by 69 publications

(70 citation statements)

References 126 publications

(288 reference statements)

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“…The MH13 adiabats cross the Morales et al [] phase diagram such that helium rain out occurs between ∼100 and 300 GPa [ Militzer et al , ]. This is consistent with the subsolar Y measurement made by the Galileo entry probe [ von Zahn et al , ].…”

Section: Methodssupporting

confidence: 76%

“…Different equations of state affect model outcomes in part by placing constraints on the allowable abundance and distribution of heavy elements. The DFT‐MD isentrope consistent with the Galileo probe measurements has higher densities and a less steep isentropic temperature profile than SCvH in the vicinity of the metallization transition [ Militzer , ; Militzer et al , ]. The H‐Reos equation of state has a similar shape to the T ( P ) profile but has an offset in temperature of several hundred thousands through much of the molecular envelope [ Nettelmann et al , ; Hubbard and Militzer , ; Miguel et al , ].…”

Section: Methodsmentioning

confidence: 95%

See 1 more Smart Citation

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

Wahl

Hubbard

Militzer

et al. 2017

Geophysical Research Letters

350

361

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The Juno spacecraft has measured Jupiter's low‐order, even gravitational moments, J2–J8, 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 Jn 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 a 7–25 Earth mass of heavy elements. We discuss the current difficulties in reconciling measured Jn with the equations of state and with theory for formation and evolution of the planet.

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Section: Methodssupporting

confidence: 76%

Section: Methodsmentioning

confidence: 95%

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

Wahl

Hubbard

Militzer

et al. 2017

Geophysical Research Letters

350

361

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“…Since a few decades the link between the uncertainty of the H EOS and the internal structure of Jupiter (and other gaseous planets) has been investigated and many efforts to model Jupiter's interior have been carried 1,[5][6][7] . The computation of an EOS from first principles requires to solve a many-body quantum mechanical problem, a task which is beyond the currently available theoretical and computational capabilities.…”

mentioning

confidence: 99%

Phase Diagram of Hydrogen and a Hydrogen-Helium Mixture at Planetary Conditions by Quantum Monte Carlo Simulations

2018

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Understanding planetary interiors is directly linked to our ability of simulating exotic quantum mechanical systems such as hydrogen (H) and hydrogen-helium (H-He) mixtures at high pressures and temperatures 1 . Equations of State (EOSs) tables based on Density Functional Theory (DFT), are commonly used by planetary scientists, although this method allows only for a qualitative description of the phase diagram 2 , due to an incomplete treatment of electronic interactions 3 . Here we report Quantum Monte Carlo (QMC) molecular dynamics simulations of pure H and H-He mixture. We calculate the first QMC EOS at 6000 K for an H-He mixture of a proto-solar composition, and show the crucial influence of He on the H metallization pressure. Our results can be used to calibrate other EOS calculations and are very timely given the accurate determination of Jupiter's gravitational field from the NASA Juno mission and the effort to determine its structure 4 .Since a few decades the link between the uncertainty of the H EOS and the internal structure of Jupiter (and other gaseous planets) has been investigated and many efforts to model Jupiter's interior have been carried 1,5-7 . The computation of an EOS from first principles requires to solve a many-body quantum mechanical problem, a task which is beyond the currently available theoretical and computational capabilities. In practice, we must resort to several approximations. The first is to decouple the ionic and electronic problems and consider the ions as classical or quantum particles, determining their motion by following the Born-Oppenheimer potential energy surface. The second approximation concerns the description of the electronic interaction and the exchange one, due to the Pauli exclusion principle.The standard approach to EOS calculations relies on Density Functional Theory (DFT), which targets the tridimensional electronic density rather than the (N e electrons) many-body wave-function. Its success and simplicity have lead to a widespread application in materials science and to the development of several software packages which allow fast and reproducible calculations 8 . Although DFT is formally exact, the explicit functional form to describe the exchange and correlation (XC) effects between electrons remains approximated 3 . Indeed, a systematic and efficient route to improve XC functional is still lacking. Therefore, in practical solid state calculations, benchmarks against experimental data, are often required to validate the XC functional used to describe the system in a satisfactory manner.Dense hydrogen systems, both in the low temperature solid and in the liquid phase remain a challenge to DFT simulations due to the interplay of strong correlation and non-covalent interactions between the atoms. DFT calculations with different functionals produce different results with the expected metallization pressure varying over a range of 100-200 GPa (Fig. 1) 12,13 . Since experimental data are limited, it is not possible to identify a posteriori the best functional...

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“…In‐site measurements of Jupiter's outermost atmosphere from the Galileo probe yielded the helium mass fraction of Y /( X + Y ) = 0.238 ± 0.007, which is smaller than the protosolar value of Y proto /( X proto + Y proto ) = 0.277 ± 0.006 (Serenelli and Basu, 2010). The measured atmospheric helium depletion has been understood in Guillot et al (1997) and Militzer et al (2016) as helium droplets raining down in Jupiter's atmosphere. In order to gain insight into this, we consider the hydrogen–helium mixture and analyze the distribution of helium in the envelope.…”

Section: Model Resultsmentioning

confidence: 99%

Signature of helium rain and dilute cores in Jupiter's interior from empirical equations of state

2020

Earth and Planetary Physics

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Measurements of Jupiter's gravity field by Juno have been acquired with unprecedented precision, but uncertainties in the planet’s hydrogen–helium equation of state (EOS) and the hydrogen–helium phase separation have meant that differences remain in the interior model predictions. We deduce an empirical EOS fromJuno gravity field observations in terms of the hydrostatic equation and then investigate the structure and composition of Jupiter by comparison of the empirical EOS with Jupiter's adiabats obtained from the physical EOS. The deduced helium mass fraction suggests depletion of helium in the outermost atmosphere and helium concentration in the inner molecular hydrogen region, which is a signature of helium rain in Jupiter's interior. The deduced envelope metallicity (the heavy‐element mass fraction) is as high in the innermost envelope as 11–13 times the solar value. Such a high metallicity provides sharp support to the dilute core model with the heavy elements dissolved in hydrogen and expanded outward. No matter how the core mass is varied, the empirical EOS derived from the two‐layer interior model generally suggests higher densities in the innermost envelope than does the best‐fit Jupiter's adiabat; this result is, again, a signature of dilute cores in Jupiter's interior. Moreover, no matter the core mass, the empirical EOS is found to exhibit an inflexion point in the deep interior, around 10 Mbar, which can be explained as the combined effect of helium concentration in the upper part and dilute cores in the lower part.

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Understanding Jupiter's interior

Cited by 69 publications

References 126 publications

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

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

Phase Diagram of Hydrogen and a Hydrogen-Helium Mixture at Planetary Conditions by Quantum Monte Carlo Simulations

Signature of helium rain and dilute cores in Jupiter's interior from empirical equations of state

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