Giant Planets from the Inside-Out

Guillot, T.; Fletcher, Leigh; Helled, Ravit; Ikoma, Masahiro; Line, Michael R.; Parmentier, Vivien

doi:10.48550/arxiv.2205.04100

Cited by 28 publications

(36 citation statements)

References 129 publications

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“…We recall that 𝐶 t and 𝜖 differ only by 𝑘 2 , which is around 1/2 for giant gaseous planets, like Jupiter and Saturn, and also possibly for Hot Jupiters (e.g. Guillot et al 2022). For a 𝑛 = 1 non-rotating polytrope, a similar value is found, but can vary with rotation to between 0.3 and 1.2 (Dewberry & Lai 2022).…”

Section: Importance Of Nonlinear Effects For Exoplanetary Systemssupporting

confidence: 54%

The effects of nonlinearities on tidal flows in the convective envelopes of rotating stars and planets in exoplanetary systems

Astoul¹,

Barker²

2022

Preprint

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In close exoplanetary systems, tidal interactions drive orbital and spin evolution of planets and stars over long timescales. Tidally-forced inertial waves (restored by the Coriolis acceleration) in the convective envelopes of low-mass stars and giant gaseous planets contribute greatly to the tidal dissipation when they are excited and subsequently damped (e.g. through viscous friction), especially early in the life of a system. These waves are known to be subject to nonlinear effects, including triggering differential rotation in the form of zonal flows. In this study, we use a realistic tidal body forcing to excite inertial waves through the residual action of the equilibrium tide in the momentum equation for the waves. By performing 3D nonlinear hydrodynamical simulations in adiabatic and incompressible convective shells, we investigate how the addition of nonlinear terms affects the tidal flow properties, and the energy and angular momentum redistribution. In particular, we identify and justify the removal of terms responsible for unphysical angular momentum evolution observed in a previous numerical study. Within our new set-up, we observe the establishment of strong cylindrically-sheared zonal flows, which modify the tidal dissipation rates from prior linear theoretical predictions. We demonstrate that the effects of this differential rotation on the waves neatly explains the discrepancies between linear and nonlinear dissipation rates in many of our simulations. We also highlight the major role of both corotation resonances and parametric instabilities of inertial waves, which are observed for sufficiently high tidal forcing amplitudes or low viscosities, in affecting the tidal flow response.

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Section: Importance Of Nonlinear Effects For Exoplanetary Systemssupporting

confidence: 54%

The effects of nonlinearities on tidal flows in the convective envelopes of rotating stars and planets in exoplanetary systems

Astoul¹,

Barker²

2022

Preprint

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“…Our model shows that the atmospheric C/O increases and that the corresponding C/H and O/H decrease with an increasing planetary formation location; this is in line with the studies referenced in the previous sentence. Our results and conclusions apply under the assumption that the atmospheric composition is a tracer of the bulk composition (but see Helled et al 2021;Guillot et al 2022).…”

Section: Discussionmentioning

confidence: 50%

“…We note that planets growing in discs with higher viscosities migrate farther and are generally more massive than planets growing in discs with lower viscosities (Schneider & Bitsch 2021a). (Helled et al 2021;Guillot et al 2022). If compositional gradients inside of the planet exist, then the atmospheric abundances only represent the minimum abundance of a specific chemical element.…”

Section: Model Limitationsmentioning

confidence: 62%

“…The main assumption of our model is that we can use the atmospheric abundances as a tracer for the bulk abundances of the giant planets. However, this assumption is certainly under debate (Helled et al 2021;Guillot et al 2022). If compositional gradients inside of the planet exist, then the atmospheric abundances only represent the minimum abundance of a specific chemical element.…”

Section: Model Limitationsmentioning

confidence: 99%

“…Even though evidence seems to indicate that the atmospheric abundance is not a tracer of the bulk abundances (e.g., Helled et al 2021;Guillot et al 2022), in also considering recent constraints from Jupiter (Wahl et al 2017;Vazan et al 2018;Debras & Chabrier 2019;Miguel et al 2022) and Saturn (Mankovich & Fuller 2021), we nevertheless adopt -for simplicity -the assumption that the atmospheric abundance is a tracer of the bulk abundances. In this work we focus on planet formation simulations in disks governed by pebble growth, drift, and evaporation to study the atmospheric abundances of growing and migrating planets.…”

Section: Introductionmentioning

confidence: 99%

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How drifting and evaporating pebbles shape giant planets

Bitsch

Kreidberg

2022

A&A

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Atmospheric abundances of exoplanets are thought to constrain the planet formation pathway, because different species evaporate at different temperatures and thus radii in the protoplanetary disc, leaving distinct signatures inside the accreted planetary atmosphere. In particular the planetary C/O ratio is thought to constrain the planet formation pathway, because of the condensation sequence of H 2 O, CO 2 , CH 4 , and CO, resulting in an increase of the gas phase C/O ratio with increasing distance to the host star. Here we use a disc evolution model including pebble growth, drift and evaporation coupled with a planet formation model that includes pebble and gas accretion as well as planet migration to compute the atmospheric compositions of giant planets. We compare our results to the recent observational constraints of the hot Jupiters WASP-77A b and τ Boötis b. WASP-77A b's atmosphere features sub-solar C/H, O/H, H 2 O/H with slightly super-solar C/O, while τ Boötis b's atmosphere features super-solar C/H, O/H and C/O with sub-solar H 2 O/H. Our simulations qualitatively reproduce these measurements and show that giants like WASP-77A b should start to form beyond the CO 2 evaporation front, while giants like τ Boötis b should originate from beyond the water ice line. Our model allows the formation of sub-and super-solar atmospheric compositions within the same framework. On the other hand, simulations without pebble evaporation, as used in classical models, can not reproduce the super-solar C/H and O/H ratios of τ Boötis b's atmosphere without the additional accretion of solids. Furthermore, we identify the α viscosity parameter of the disc as a key ingredient regarding planetary composition, because the viscosity drives the inward motion of volatile enriched vapor, responsible for the accretion of gaseous carbon and oxygen. Depending on the planet's migration history through the disc across different evaporation fronts, orderof-magnitude differences in atmospheric carbon and oxygen abundance should be expected. Our simulations additionally predict super-solar N/H for τ Boötis b and solar N/H for WASP-77A b. We conclude thus that pebble evaporation is a key ingredient to explain the variety of exoplanet atmospheres, because it can explain both, sub-and super-solar atmospheric abundances.

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The Deep Oxygen Abundance in Solar System Giant Planets, with a New Derivation for Saturn

Cavalié,

Lunine,

Mousis

et al. 2024

Space Sci Rev

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Deep elemental composition is a challenging measurement to achieve in the giant planets of the solar system. Yet, knowledge of the deep composition offers important insights in the internal structure of these planets, their evolutionary history and their formation scenarios. A key element whose deep abundance is difficult to obtain is oxygen, because of its propensity for being in condensed phases such as rocks and ices. In the atmospheres of the giant planets, oxygen is largely stored in water molecules that condense below the observable levels. At atmospheric levels that can be investigated with remote sensing, water abundance can modify the observed meteorology, and meteorological phenomena can distribute water through the atmosphere in complex ways that are not well understood and that encompass deeper portions of the atmosphere. The deep oxygen abundance provides constraints on the connection between atmosphere and interior and on the processes by which other elements were trapped, making its determination an important element to understand giant planets. In this paper, we review the current constraints on the deep oxygen abundance of the giant planets, as derived from observations and thermochemical models.

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Giant Planets from the Inside-Out

Cited by 28 publications

References 129 publications

The effects of nonlinearities on tidal flows in the convective envelopes of rotating stars and planets in exoplanetary systems

The effects of nonlinearities on tidal flows in the convective envelopes of rotating stars and planets in exoplanetary systems

How drifting and evaporating pebbles shape giant planets

The Deep Oxygen Abundance in Solar System Giant Planets, with a New Derivation for Saturn

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