Bifurcation in the history of Uranus and Neptune: the role of giant impacts

Abstract

Despite many similarities, there are significant observed differences between Uranus and Neptune: while Uranus is tilted and has a regular set of satellites, suggesting their accretion from a disk, Neptune's moons are irregular and are captured objects. In addition, Neptune seems to have an internal heat source, while Uranus is in equilibrium with solar insulation. Finally, structure models based on gravity data suggest that Uranus is more centrally condensed than Neptune. We perform a large suite of high resolution SPH simulations to investigate whether these differences can be explained by giant impacts. For Uranus, we find that an oblique impact can tilt its spin axis and eject enough material to create a disk where the regular satellites are formed. Some of the disks are massive and extended enough, and consist of enough rocky material to explain the formation of Uranus' regular satellites. For Neptune, we investigate whether a head-on collision could mix the interior, and lead to an adiabatic temperature profile, which may explain its larger flux and higher moment of inertia value. We find that massive and dense projectiles can penetrate towards the centre and deposit mass and energy in the deep interior, leading to a less centrally concentrated interior for Neptune. We conclude that the dichotomy between the ice giants can be explained by violent impacts after their formation.

arXiv comment18 pages, 15 figures, 1 table, accepted to MNRAS

References in corpus (36)

• HEALPix -- a Framework for High Resolution Discretization, and Fast Analysis of Data Distributed on the Sphere
• Catastrophic disruptions revisited
• Improving convergence in smoothed particle hydrodynamics simulations without pairing instability
• Gasoline: An adaptable implementation of TreeSPH
• Fundamental differences between SPH and grid methods
• Collisions between Gravity-Dominated Bodies: 2. The Diversity of Impact Outcomes during the End Stage of Planet Formation
• Collisions Between Gravity-Dominated Bodies: 1. Outcome Regimes and Scaling Laws
• Modelling discontinuities and Kelvin-Helmholtz instabilities in SPH
• Inviscid SPH
• Gasoline2: A Modern SPH Code
• Interior Models of Uranus and Neptune
• New indication for a dichotomy in the interior structure of Uranus and Neptune from the application of modified shape and rotation data
• Melting and Mixing States of the Earth's Mantle after the Moon-Forming Impact
• A Density Independent Formulation of Smoothed Particle Hydrodynamics
• Formation of Regular Satellites from Ancient Massive Rings in the Solar System
• The gravitational and hydrodynamical interaction between the LMC and the Galaxy
• Resolving mixing in Smoothed Particle Hydrodynamics
• Young Solar System's Fifth Giant Planet?
• Self-Consistent Model Atmospheres and the Cooling of the Solar System's Giant Planets
• Uranus evolution models with simple thermal boundary layers
• NOTE: Explaining why the Uranian satellites have equatorial prograde orbits despite the large planetary obliquity
• Lunar accretion from a Roche-interior fluid disk
• The Formation of Jupiter's Diluted Core by a Giant Impact
• Uranus and Neptune: Shape and Rotation
• Forming Mercury by Giant Impacts
• Consequences of Giant Impacts on Early Uranus for Rotation, Internal Structure, Debris, and Atmospheric Erosion
• A collisionless scenario for Uranus tilting
• Effect of Non-Adiabatic Thermal Profiles on the Inferred Compositions of Uranus and Neptune
• Numerical aspects of Giant Impact simulations
• Planetary Giant Impacts: Convergence of High-Resolution Simulations using Efficient Spherical Initial Conditions and SWIFT
• What do we Really Know about Uranus and Neptune?
• In Situ Formation of Icy Moons of Uranus and Neptune
• Primordial Earth mantle heterogeneity caused by the Moon-forming giant impact
• The Exchange of Mass and Angular Momentum in the Impact Event of Ice Giant Planets: Implications for the origin of Uranus
• A comparison of SPH artificial viscosities and their impact on the Keplerian disk
• Last giant impact on the Neptunian system. Constraints on oligarchic masses in the trans-Saturnian region

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• Uranian Satellite Formation by Evolution of a Water Vapor Disk Generated by a Giant Impact
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• Forming Iron-rich Planets with Giant Impacts
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• Key Atmospheric Signatures for Identifying the Source Reservoirs of Volatiles in Uranus and Neptune
• Tilting Uranus via the migration of an ancient satellite
• Machine learning applied to simulations of collisions between rotating, differentiated planets
• Co-accretion + giant impact origin of the Uranus system: Tilting Impact
• Leaning Sideways: VHS 1256-1257 b is a Super-Jupiter with a Uranus-like Obliquity
• The EOS/Resolution Conspiracy: Convergence in Proto-Planetary Collision Simulations
• Collision Chains among the Terrestrial Planets. II. An Asymmetry between Earth and Venus
• The interior of Uranus: Thermal profile, bulk composition and the distribution of rock, water and hydrogen and helium
• Could Uranus and Neptune form by collisions of planetary embryos?
• REMIX SPH -- improving mixing in smoothed particle hydrodynamics simulations using a generalised, material-independent approach
• Tilting Uranus via Secular Spin-Orbit Resonance with Planet 9
• A scaling relation for core heating by giant impacts and implications for dynamo onset
• On the origin of Jupiter's fuzzy core: constraints from N-body, impact and evolution simulations
• Spectral trends across the rings and inner moons of Uranus and Neptune from JWST NIRCam images
• A Systematic Survey of Moon-Forming Giant Impacts. II. Rotating bodies
• The Outcome of Collisions between Gaseous Clumps formed by Disk Instability
• Planet Formation
• Exploring the catastrophic regime: thermodynamics and disintegration in head-on planetary collisions
• Protoplanet collisions: new scaling laws from SPH simulations
• Early evidence for isotropic planetary obliquities in young super-Jupiter systems
• Dealing with density discontinuities in planetary SPH simulations
• Obliquity Constraints on the Planetary-mass Companion HD 106906 b
• The possibility of a giant impact on Venus
• Icy or rocky? Convective or stable? New interior models of Uranus and Neptune
• Reassessing planetary composition: Evidence of rock-dominated envelopes in Uranus and Neptune
• Did Uranus' regular moons form via a rocky giant impactor?
• Deuterated water and the formation of the satellites of Uranus
• Possible in situ formation of Uranus and Neptune via Pebble Accretion