Forming Mercury by Giant Impacts

Abstract

The origin of Mercury's high iron-to-rock ratio is still unknown. In this work we investigate Mercury's formation via giant impacts and consider the possibilities of a single giant impact, a hit-and-run, and multiple collisions in one theoretical framework. We study the standard collision parameters (impact velocity, mass ratio, impact parameter), along with the impactor's composition and the cooling of the target. It is found that the impactor's composition affects the iron distribution within the planet and the final mass of the target by up to 15\%, although the resulting mean iron fraction is similar. We suggest that an efficient giant impact requires to be head-on with high velocities, while in the hit-and-run case the impact can occur closer to the most probable collision angle (45${}^{\circ }$). It is also shown that Mercury's current iron-to-rock ratio can be a result of multiple-collisions, with their exact number depending on the collision parameters. Mass loss is found to be more significant when the collisions are tight in time.

arXiv comment21 pages, 10 figures, 4 tables, accepted for publication in ApJ

References in corpus (20)

• Catastrophic disruptions revisited
• Gasoline: An adaptable implementation of TreeSPH
• 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
• The origin of the Moon within a terrestrial synestia
• Atmospheric Mass Loss During Planet Formation: The Importance of Planetesimal Impacts
• Merging Criteria for Giant Impacts of Protoplanets
• Collisional Stripping and Disruption of Super-Earths
• The Frequency of Giant impacts on Earth-like Worlds
• Photophoretic separation of metals and silicates: the formation of Mercury like planets and metal depletion in chondrites
• Mercurian impact ejecta: Meterorites and mantle
• Coupling SPH and thermochemical models of planets: Methodology and example of a Mars-sized body
• Numerical aspects of Giant Impact simulations
• SPH calculations of Mars-scale collisions: the role of the Equation of State, material rheologies, and numerical effects
• Resolution Dependence of Disruptive Collisions between Planetesimals in the Gravity Regime
• Collisional stripping of planetary crusts
• Transfer, loss and physical processing of water in hit-and-run collisions of planetary embryos
• Terrestrial Planet Formation: Constraining the Formation of Mercury
• Unconvergence of Very Large Scale GI Simulations
• Collisional Disruption of Planetesimals in the Gravity Regime with iSALE Code: Comparison with SPH code for Purely Hydrodynamic Bodies

Cited by in corpus (55)

• Cool Jupiters greatly outnumber their toasty siblings: Occurrence rates from the Anglo-Australian Planet Search
• The New Generation Planetary Population Synthesis (NGPPS). II. Planetary population of solar-like stars and overview of statistical results
• A giant impact as the likely origin of different twins in the Kepler-107 exoplanet system
• Bifurcation in the history of Uranus and Neptune: the role of giant impacts
• Solar System Physics for Exoplanet Research
• Loss and fractionation of noble gas isotopes and moderately volatile elements from planetary embryos and early Venus, Earth and Mars
• Impact of the measured parameters of exoplanets on the inferred internal structure
• Nucleation and growth of iron pebbles explains the formation of iron-rich planets akin to Mercury
• Extreme Debris Disk Variability -- Exploring the Diverse Outcomes of Large Asteroid Impacts During the Era of Terrestrial Planet Formation
• Rocklines as Cradles for Refractory Solids in the Protosolar Nebula
• 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
• Dynamical Constraints on Mercury's Collisional Origin
• Constraining the Formation of the Four Terrestrial Planets in the Solar System
• Forming Iron-rich Planets with Giant Impacts
• The terrestrial planet formation paradox inferred from high-resolution N-body simulations
• Where are the Extrasolar Mercuries?
• Forming super-Mercuries: The role of stellar abundances
• Carbon monoxide gas produced by a giant impact in the inner region of a young system
• Collision Chains among the Terrestrial Planets. III. Formation of the Moon
• Fate of the runner in hit-and-run collisions
• Dynamical avenues for Mercury's origin I: The lone survivor of a primordial generation of short-period proto-planets
• The Role of Giant Impacts in Planet Formation
• Dynamical avenues for Mercury's origin II: in-situ formation in the inner terrestrial disk
• Modeling the Formation of the Family of the Dwarf Planet Haumea
• The early instability scenario: Mars' mass explained by Jupiter's orbit
• Machine learning applied to simulations of collisions between rotating, differentiated planets
• The EOS/Resolution Conspiracy: Convergence in Proto-Planetary Collision Simulations
• The Exosphere as a Boundary: Origin and Evolution of Airless Bodies in the Inner Solar System and Beyond Including Planets with Silicate Atmospheres
• Collision Chains among the Terrestrial Planets. II. An Asymmetry between Earth and Venus
• Modification of the composition and density of Mercury from late accretion
• Explaining Mercury via a single giant impact is highly unlikely
• Could Uranus and Neptune form by collisions of planetary embryos?
• Tidally-Distorted, Iron-Enhanced Exoplanets Closely Orbiting Their Stars
• Atmospheric Mass Loss from High Velocity Giant Impacts
• Mercury's formation within the Early Instability Scenario
• Collisional formation of massive exomoons of super-terrestrial exoplanets
• Extreme close encounters between proto-Mercury and proto-Venus in terrestrial planet formation
• Residual Neural Networks for the Prediction of Planetary Collision Outcomes
• On the origin of Jupiter's fuzzy core: constraints from N-body, impact and evolution simulations
• Hypothetical hyperbolic encounters between Venus and proto-Mercury that partially \ stripped away proto-Mercury's mantle
• The influence of Equation of State on impact dynamics between Pluto-like bodies
• The Outcome of Collisions between Gaseous Clumps formed by Disk Instability
• Exploring the catastrophic regime: thermodynamics and disintegration in head-on planetary collisions
• A sub-Neptune transiting the young field star HD 18599 at 40 pc
• Protoplanet collisions: new scaling laws from SPH simulations
• Dealing with density discontinuities in planetary SPH simulations
• Origins of Mercury's Big Heart of Iron: Exploring Pathways to Form High Core Mass Fraction (CMF) Planets via N-body Simulations
• Formation of the four terrestrial planets in the Jupiter-Saturn chaotic excitation scenario: fundamental properties and water delivery
• The possibility of a giant impact on Venus
• The energy budgets of giant impacts
• Evolution of Mercury's Earliest Atmosphere
• Re-accretion of Giant Impact Ejecta Can Drive Significant Atmospheric Erosion on Terrestrial Planets
• What the Solar System Can Teach Us About Rocky Exoplanets
• Magnitude of stable iron isotope fractionation limited by multiple stages of terrestrial core formation