The Role of Giant Impacts in Planet Formation
arXiv:2312.15018 · doi:10.1146/annurev-earth-031621-055545
Abstract
Planets are expected to conclude their growth through a series of giant impacts: energetic, global events that significantly alter planetary composition and evolution. Computer models and theory have elucidated the diverse outcomes of giant impacts in detail, improving our ability to interpret collision conditions from observations of their remnants. However, many open questions remain, as even the formation of the Moon, a widely suspected giant-impact product for which we have the most information, is still debated. We review giant-impact theory, the diverse nature of giant-impact outcomes, and the governing physical processes. We discuss the importance of computer simulations, informed by experiments, for accurately modeling the impact process. Finally, we outline how the application of probability theory and computational advancements can assist in inferring collision histories from observations, and we identify promising opportunities for advancing giant-impact theory in the future. Giant impacts exhibit diverse possible outcomes leading to changes in planetary mass, composition, and thermal history depending on the conditions. Improvements to computer simulation methodologies and new laboratory experiments provide critical insights into the detailed outcomes of giant impacts. When colliding planets are similar in size, they can merge or escape one another with roughly equal probability, but with different effects on their resulting masses, densities, and orbits. Different sequences of giant impacts can produce similar planets, encouraging the use of probability theory to evaluate distinct formation hypotheses.
arXiv commentPublished open-access article posted with permission from journal
References in corpus (61)
- Protoplanetary Disks and Their Evolution
- Catastrophic disruptions revisited
- Fundamental differences between SPH and grid methods
- Solar System evolution from compositional mapping of the asteroid belt
- Building Terrestrial Planets
- Collisions Between Gravity-Dominated Bodies: 1. Outcome Regimes and Scaling Laws
- Collisions between Gravity-Dominated Bodies: 2. The Diversity of Impact Outcomes during the End Stage of Planet Formation
- Can we constrain interior structure of rocky exoplanets from mass and radius measurements?
- The origin of the Moon within a terrestrial synestia
- Formation of planetary systems by pebble accretion and migration: How the radial pebble flux determines a terrestrial-planet or super-Earth growth mode
- Growing the gas-giant planets by the gradual accumulation of pebbles
- A hit-and-run Giant Impact scenario
- Modeling the Formation of Giant Planet Cores I: Evaluating Key Processes
- Resolving mixing in Smoothed Particle Hydrodynamics
- Minimum Radii of Super-Earths: Constraints from Giant Impacts
- Multiple Impact Origin for the Moon
- Debris from terrestrial planet formation: the Moon-forming collision
- Highly siderophile elements were stripped from Earth's mantle by iron sulfide segregation
- Debris from giant impacts between planetary embryos at large orbital radii
- Collisional Stripping and Disruption of Super-Earths
- The Frequency of Giant impacts on Earth-like Worlds
- SPH calculations of asteroid disruptions: The role of pressure dependent failure models
- The Formation of the Collisional Family around the Dwarf Planet Haumea
- The GENGA Code: Gravitational Encounters in N-body simulations with GPU Acceleration
- Large Impacts around a Solar Analog Star in the Era of Terrestrial Planet Formation
- CRKSPH - A Conservative Reproducing Kernel Smoothed Particle Hydrodynamics Scheme
- Investigation of the Initial State of the Moon-Forming Disk: Bridging SPH Simulations and Hydrostatic Models
- Giant Impact: An Efficient Mechanism for the Devolatilization of Super-Earths
- Warm Debris Disks Produced by Giant Impacts During Terrestrial Planet Formation
- Forming Mercury by Giant Impacts
- Momentum transfer across shear flows in Smoothed Particle Hydrodynamic simulations of galaxy formation
- Scaling laws for the geometry of an impact-induced magma ocean
- Chemical Diversity of Super-Earths As a Consequence of Formation
- SPH calculations of Mars-scale collisions: the role of the Equation of State, material rheologies, and numerical effects
- Silicate Melting and Vaporization during Rocky Planet Formation
- The Formation of Pluto's Low Mass Satellites
- Nucleation and growth of iron pebbles explains the formation of iron-rich planets akin to Mercury
- Realistic On-the-fly Outcomes of Planetary Collisions II: Bringing Machine Learning to N-body Simulations
- Realistic On-The-Fly Outcomes of Planetary Collisions: Machine Learning Applied to Simulations of Giant Impacts
- Growing Mars fast: High-resolution GPU simulations of embryo formation
- Constraints on the pre-impact orbits of Solar System giant impactors
- Realistic collisional water transport during terrestrial planet formation: Self-consistent modeling by an N-body--SPH hybrid code
- Fragment properties from large-scale asteroid collisions: I: Results from SPH/N-body simulations using porous parent bodies and improved material models
- Impact Erosion Model for Gravity-Dominated Planetesimals
- Linking planetary embryo formation to planetesimal formation I: The impact of the planetesimal surface density in the terrestrial planet zone
- Unconvergence of Very Large Scale GI Simulations
- Collision Chains among the Terrestrial Planets. III. Formation of the Moon
- The Effect of Inefficient Accretion on Planetary Differentiation
- Fate of the runner in hit-and-run collisions
- Collisional heating and compaction of small bodies: Constraints for their origin and evolution
- Machine learning applied to simulations of collisions between rotating, differentiated planets
- Atmosphere Loss in Oblique Super-Earth Impacts
- Giant impacts stochastically change the internal pressures of terrestrial planets
- Can a machine learn the outcome of planetary collisions?
- Importance of Giant Impact Ejecta for Orbits of Planets Formed during the Giant Impact Era
- Graze-and-Merge Collisions under External Perturbers
- Examining the Accuracy of Astrophysical Disk Simulations With a Generalized Hydrodynamical Test Problem
- Building Terrestrial Planets: Why results of perfect-merging simulations are not quantitatively reliable approximations to accurate modeling of terrestrial planet formation
- Planet formation: key mechanisms and global models
- Statistics of collision parameters computed from 2D simulations
- SPH simulations of high-speed collisions between asteroids and comets
Cited by in corpus (6)
- Can metal-rich worlds form by giant impacts?
- Metal-silicate mixing in planetesimal collisions
- Planetary Edge Trends (PET). I. The Inner Edge-Stellar Mass Correlation
- Formation of the four terrestrial planets in the Jupiter-Saturn chaotic excitation scenario: fundamental properties and water delivery
- Episodic planetesimal disruptions triggered by dissipation of gas disk
- Re-accretion of Giant Impact Ejecta Can Drive Significant Atmospheric Erosion on Terrestrial Planets