New Models of Jupiter in the Context of Juno and Galileo

Debras, Florian; Chabrier, G.

doi:10.3847/1538-4357/aaff65

Cited by 174 publications

(227 citation statements)

References 92 publications

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“…When the inherent density of the hydrogen-helium mixture is set by the DFT equation of state, it is not possible to find simple 3-layer interior models that simultaneously match the Juno gravity solution, while satisfying atmospheric constraints on temperature and composition from the Galileo entry probe (Seiff et al 1998;von Zahn et al 1998). Satisfying all such constraints requires either more complex interior thermal and compositional structure (Debras & Chabrier 2019), contributions from deep winds (Guillot et al 2018;Kaspi et al 2018) or both (Militzer et al 2020). The requisite deep wind profile decays with depth, due to interaction of the conductive fluid with the magnetic field (Cao & Stevenson 2017), and cannot be described self-consistently using a potential based theory like CMS (Militzer et al 2019).…”

Section: Interior Modelsmentioning

confidence: 99%

Equilibrium Tidal Response of Jupiter: Detectability by the Juno Spacecraft

Wahl

Parisi

Folkner

et al. 2020

ApJ

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An observation of Jupiter's tidal response is anticipated for the on-going Juno spacecraft mission. We combine self-consistent, numerical models of Jupiter's equilibrium tidal response with observed Doppler shifts from the Juno gravity science experiment to test the sensitivity of the spacecraft to tides raised by the Galilean satellites and the Sun. The concentric Maclaurin spheroid (CMS) method finds the equilibrium shape and gravity field of a rotating, liquid planet with the tide raised by a satellite, expanded in Love numbers (k nm ). We present improvements to CMS theory that eliminate an unphysical center of mass offset and study in detail the convergence behavior of the CMS approach. We demonstrate that the dependence of k nm with orbital distance is important when considering the combined tidal response for Jupiter. Conversely, the details of the interior structure have a negligible influence on k nm , for models that match the zonal harmonics J 2 , J 4 and J 6 , already measured to high precision by Juno. As the mission continues, improved coverage of Jupiters gravity field at different phases of Ios orbit is expected to yield an observed value for the degree-2 Love number (k 22 ) and potentially select higher-degree k nm . We present a test of the sensitivity of the Juno Doppler signal to the calculated k nm , which suggests the detectability of k 33 , k 42 and k 31 , in addition to k 22 . A mismatch of a robust Juno observation with the remarkably small range in calculated Io equilibrium k 22 = 0.58976±0.0001, would indicate a heretofore uncharacterized dynamic contribution to the tides.

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Section: Interior Modelsmentioning

confidence: 99%

Equilibrium Tidal Response of Jupiter: Detectability by the Juno Spacecraft

Wahl

Parisi

Folkner

et al. 2020

ApJ

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“…It is however much more difficult to explore the transitions between them are uncertain. Furthermore, recent observational evidence from Juno gravity field measurements indicates that heavy elements are probably distributed throughout the inner regions of the planet (Wahl et al 2017;Helled & Stevenson 2017;Debras & Chabrier 2019). As a result, there has been much ongoing research in recent years to explore planetary models incorporating compositional gradients or non-adiabatic structures (Chabrier & Baraffe 2007;Leconte & Chabrier 2012;Lozovsky et al 2017;Vazan et al 2016;Berardo & Cumming 2017;Vazan et al 2018;Debras & Chabrier 2019).…”

Section: Introductionmentioning

confidence: 99%

Wave propagation in semiconvective regions of giant planets

Pontin

Barker

Hollerbach

et al. 2020

Monthly Notices of the Royal Astronomical Society

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Recent observations of Jupiter and Saturn suggest that heavy elements may be diluted in the gaseous envelope, providing a compositional gradient that could stabilise ordinary convection and produce a stably-stratified layer near the core of these planets. This region could consist of semi-convective layers with a staircase-like density profile, which have multiple convective zones separated by thin stably-stratified interfaces, as a result of double-diffusive convection. These layers could have important effects on wave propagation and tidal dissipation that have not been fully explored. We analyse the effects of these layers on the propagation and transmission of internal waves within giant planets, extending prior work in a local Cartesian model. We adopt a simplified global Boussinesq planetary model in which we explore the internal waves in a non-rotating spherical body. We begin by studying the free modes of a region containing semi-convective layers. We then analyse the transmission of internal waves through such a region. The free modes depend strongly on the staircase properties, and consist of modes with both internal and interfacial gravity wave-like behaviour. We determine the frequency shifts of these waves as a function of the number of steps to explore their potential to probe planetary internal structures. We also find that wave transmission is strongly affected by the presence of a staircase. Very large-wavelength waves are transmitted efficiently, but small-scale waves are only transmitted if they are resonant with one of the free modes. The effective size of the core is therefore larger for non-resonant modes.

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“…The Galileo entropy, which was determined in terms of the entry probe into the outmost atmosphere, could be different from the entropy of the deep interior. It has been suggested in Hubbard and Militzer (2016) and Debras and Chabrier (2019) that hydrogen–helium immiscibility brings in a higher‐entropy adiabat for interior pressures larger than 1 Mbar. The calculation of Jupiter's adiabat will be improved by using different entropies for the two envelopes.…”

Section: 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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New Models of Jupiter in the Context of Juno and Galileo

Cited by 174 publications

References 92 publications

Equilibrium Tidal Response of Jupiter: Detectability by the Juno Spacecraft

Equilibrium Tidal Response of Jupiter: Detectability by the Juno Spacecraft

Wave propagation in semiconvective regions of giant planets

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

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