In-situ enrichment in heavy elements of hot Jupiters

Abstract

Context: Radius and mass measurements of short-period giant planets reveal that many of these planets contain a large amount of heavy elements, in sharp contrast with the expectations of the conventional core-accretion model for the origin of giant planets. Aims: The proposed explanations for the heavy-element enrichment of giant planets fall short of explaining the most enriched planets. We look for additional processes that can explain the full envelope of inferred enrichments. Methods: We revisit the dynamics of pebbles and dust in the vicinity of giant planets using analytic estimates. Although our results are derived in the framework of a viscous alpha-disk we also discuss the case of disks driven by angular momentum removal in magnetized winds. Results: When giant planets are far from the star, dust and pebbles are confined in a pressure bump at the outer edge of the planet-induced gap. Instead, when the planets reach the inner part of the disk (r << 2 au), dust penetrates the gap together with the gas. The dust/gas ratio can be enhanced by more than an order of magnitude if radial drift of dust is not impeded farther out by other barriers. Thus, hot planets undergoing runaway gas accretion can swallow a large amount of dust. Conclusions: Whereas the gas accreted by giant planets in the outer disk is very dust-poor, that accreted by hot planets can be extremely dust-rich. Thus, provided that a large fraction of the atmosphere of hot-Jupiters is accreted in situ, a large amount of dust can be accreted as well. We draw a distinction between this process and pebble accretion, which is ineffective at small stellocentric radii, even for super-Earths. Giant planets farther out in the disk are extremely effective barriers against the flow of pebbles and dust across their gap.

arXiv commentIn press in Astronomy & Astrophysics

References in corpus (52)

• On the width and shape of gaps in protoplanetary disks
• Dynamics of Protoplanetary Disks
• Separating gas-giant and ice-giant planets by halting pebble accretion
• Radial Flow of Dust Particles in Accretion Disks
• The Mass-Metallicity Relation for Giant Planets
• Disk Accretion Onto High-Mass Planets
• Evolution of "51Peg b-like" Planets
• Possible Solutions to the Radius Anomalies of Transiting Giant Planets
• The Disk Substructures at High Angular Resolution Project (DSHARP) VI: Dust trapping in thin-ringed protoplanetary disks
• Mass Flow and Accretion through gaps in Accretion Discs
• Models of the in situ formation of detected extrasolar giant planets
• Reversing type II migration: resonance trapping of a lighter giant protoplanet
• A correlation between the heavy element content of transiting extrasolar planets and the metallicity of their parent stars
• Pebble isolation mass --- scaling law and implications for the formation of super-Earths and gas giants
• On the Radii of Extrasolar Giant Planets
• The structure of protoplanetary discs around evolving young stars
• Inflating Hot Jupiters With Ohmic Dissipation
• In Situ Formation and Dynamical Evolution of Hot Jupiter Systems
• Inside-Out Planet Formation
• Close-in planetesimal formation by pile-up of drifting pebbles
• On the Anomalous Radii of the Transiting Extrasolar Planets
• Heat transport in giant (exo)planets: a new perspective
• Bayesian Analysis of Hot Jupiter Radius Anomalies: Evidence for Ohmic Dissipation?
• The Migration of Gap-Opening Planets is not Locked to Viscous Disk Evolution
• Migration of massive planets in accreting disks
• How drifting and evaporating pebbles shape giant planets I: Heavy element content and atmospheric C/O
• Dust retention in protoplanetary disks
• The radial dependence of pebble accretion rates: A source of diversity in planetary systems I. Analytical formulation
• Thresholds for Particle Clumping by the Streaming Instability
• Jupiter's composition: sign of a (relatively) late formation in a chemically evolved protosolar disk
• The Mechanical Greenhouse: Burial of Heat by Turbulence in Hot Jupiter Atmospheres
• Tidal dissipation within hot Jupiters: a new appraisal
• Characterizing the variable dust permeability of planet-induced gaps
• Formation of Giant Planet Satellites
• Radiation hydrodynamical models of the inner rim in protoplanetary disks
• A systematic description of wind-driven protoplanetary discs
• CoRoT: harvest of the exoplanet program
• Ring formation and dust dynamics in wind-driven protoplanetary discs: global simulations
• Toward a new paradigm for Type II migration
• The origin of the high metallicity of close-in giant exoplanets: Combined effect of the resonant and aerodynamic shepherding
• Leaky dust traps: How fragmentation impacts dust filtering by planets
• Gas and multi-species dust dynamics in viscous protoplanetary discs: the importance of the dust back-reaction
• Quasi-static contraction during runaway gas accretion onto giant planets
• The composition of transiting giant extrasolar planets
• Jupiter's heavy-element enrichment expected from formation models
• Stellar irradiated discs and implications on migration of embedded planets III: viscosity transitions
• Three-dimensional Global Simulations of Type-II Planet-disk Interaction with a Magnetized Disk Wind: I. Magnetic Flux Concentration and Gap Properties
• A Self-Consistent Model for Dust-Gas Coupling in Protoplanetary Disks
• The origin of the high metallicity of close-in giant exoplanets II The nature of the sweet spot for accretion
• Shallowness of circulation in hot Jupiters -- Advancing the Ohmic dissipation model
• Migration of pairs of giant planets in low-viscosity discs
• Laboratory Experiments on the Motion of Dense Dust Clouds

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• An M dwarf accompanied by a close-in giant orbiter with SPECULOOS
• BOWIE-ALIGN: JWST reveals hints of planetesimal accretion and complex sulphur chemistry in the atmosphere of the misaligned hot Jupiter WASP-15b
• Revising the Giant Planet Mass-Metallicity Relation: Deciphering the Formation Sequence of Giant Planets
• Which stars can form planets: Planetesimal formation at low metallicities
• Three-dimensional transport of solids in a protoplanetary disk containing a growing giant planet
• Three Warm Jupiters around Solar-analog stars detected with TESS
• There is no disk mass budget problem of planet formation