Explaining Mercury via a single giant impact is highly unlikely
arXiv:2207.14774 · doi:10.1093/mnras/stac2183
Abstract
The classical scenario of terrestrial planet formation is characterized by a phase of giant impacts among Moon-to-Mars mass planetary embryos. While the classic model and its adaptations have produced adequate analogs of the outer three terrestrial planets, Mercury's origin remains elusive. Mercury's high-core mass fraction compared to the Earth's is particularly outstanding. Among collisional hypotheses, this feature has been long interpreted as the outcome of an energetic giant impact among two massive protoplanets. Here, we revisit the classical scenario of terrestrial planet formation with focus on the outcome of giant impacts. We have performed a large number of N-body simulations considering different initial distributions of planetary embryos and planetesimals. Our simulations tested the effects of different giant planet configurations, from virtually circular to very eccentric configurations. We compare the giant impacts produced in our simulations with those that are more likely to account for the formation of Mercury and the Moon according to smoothed hydrodynamic simulations. Impact events that could lead to Moon's formation are observed in all our simulations with up to ~20% of all giant impacts, consistent with the range of the expected Moon-forming event conditions. On the other hand, Mercury-forming events via a single giant impact are extremely rare, accounting for less than ~1% of all giant impacts. Our results suggest that producing Mercury as a remnant of a single giant impact that strips out the mantle of a differentiated planetary object with Earth-like iron-silicate ratio is challenging and alternative scenarios may be required (e.g. multiple collisions).
arXiv commentAccepted for publications in MNRAS
References in corpus (63)
- A low mass for Mars from Jupiter's early gas-driven migration
- Building Terrestrial Planets
- Building the Terrestrial Planets: Constrained Accretion in the Inner Solar System
- 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
- High-resolution simulations of the final assembly of Earth-like planets 1: terrestrial accretion and dynamics
- Formation of the Terrestrial Planets from a Narrow Annulus
- Origin of water in the inner Solar System: Planetesimals scattered inward during Jupiter and Saturn's rapid gas accretion
- Water Delivery and Giant Impacts in the 'Grand Tack' Scenario
- The timeline of the Lunar bombardment - revisited
- Highly Siderophile Elements in the Earth's Mantle as a Clock for the Moon-forming Impact
- Close-in planetesimal formation by pile-up of drifting pebbles
- A hit-and-run Giant Impact scenario
- Growing the terrestrial planets from the gradual accumulation of sub-meter sized objects
- Mars' Growth Stunted by an Early Giant Planet Instability
- Merging Criteria for Giant Impacts of Protoplanets
- Gas disks to gas giants: Simulating the birth of planetary systems
- Formation of Terrestrial Planets from Protoplanets under a Realistic Accretion Condition
- Constructing the secular architecture of the solar system II: The terrestrial planets
- Planetesimal rings as the cause of the Solar System's planetary architecture
- Terrestrial Planet Formation in Disks with Varying Surface Density Profiles
- The Frequency of Giant impacts on Earth-like Worlds
- The structure of terrestrial bodies: Impact heating, corotation limits and synestias
- The early instability scenario: terrestrial planet formation during the giant planet instability, and the effect of collisional fragmentation
- Terrestrial Planet Formation Constrained by Mars and the Structure of the Asteroid Belt
- Formation, stratification, and mixing of the cores of Earth and Venus
- The Feeding Zones of Terrestrial Planets and Insights into Moon Formation
- Compositional evolution during rocky protoplanet accretion
- A Compound model for the origin of Earth's water
- Terrestrial Planet Formation in a protoplanetary disk with a local mass depletion: A successful scenario for the formation of Mars
- A Collisional Origin to Earth's Non-chondritic Composition?
- Forming Mercury by Giant Impacts
- Outward migration of Jupiter and Saturn in 3:2 or 2:1 resonance in radiative disks: implications for the Grand Tack and Nice models
- Early Solar System instability triggered by dispersal of the gaseous disk
- Equilibrium Condensation from Chondritic Porous IDP Enriched Vapor: Implications for Mercury and Enstatite Chondrite Origins
- Planetesimals to Terrestrial Planets: collisional evolution amidst a dissipating gas disk
- Photophoretic separation of metals and silicates: the formation of Mercury like planets and metal depletion in chondrites
- Mercurian impact ejecta: Meterorites and mantle
- The Role of Early Giant Planet Instability in the Terrestrial Planet Formation
- The excitation of a primordial cold asteroid belt as an outcome of the planetary instability
- Terrestrial Planet Formation During the Migration and Resonance Crossings of the Giant Planets
- Nucleation and growth of iron pebbles explains the formation of iron-rich planets akin to Mercury
- The Elusive Origin of Mercury
- Terrestrial planet formation by torque-driven convergent migration of planetary embryos
- Seeding the Formation of Mercurys: An Iron-sensitive Bouncing Barrier in Disk Magnetic Fields
- Formation of compact systems of super-Earths via dynamical instabilities and giant impacts
- Numerically Predicted Indirect Signatures of Terrestrial Planet Formation
- The effect of a strong pressure bump in the Sun's natal disk: Terrestrial planet formation via planetesimal accretion rather than pebble accretion
- Constraints on the pre-impact orbits of Solar System giant impactors
- Dynamical Constraints on Mercury's Collisional Origin
- Constraining the Formation of the Four Terrestrial Planets in the Solar System
- Did Jupiter's core form in the innermost parts of the Sun's protoplanetary disk?
- Terrestrial Planet Formation: Constraining the Formation of Mercury
- Composition and Size Dependent Sorting in Preplanetary Growth: Seeding the Formation of Mercury-like Planets
- The "Breaking The Chains" migration model for super-Earths formation: the effect of collisional fragmentation
- Dynamical Evolution of the Earth-Moon Progenitors - Whence Theia?
- Formation of Terrestrial Planets
- 2D condensation model for the inner Solar Nebula: an enstatite-rich environment
- Dynamical avenues for Mercury's origin I: The lone survivor of a primordial generation of short-period proto-planets
- Born extra-eccentric: A broad spectrum of primordial configurations of the gas giants that match their present-day orbits
- Exogenous delivery of water to Mercury
- Can a jumping-Jupiter trigger the Moon's formation impact?
- Physical properties of terrestrial planets and water delivery in the habitable zone using N-body simulations with fragmentation