The early impact histories of meteorite parent bodies

Abstract

We have developed a statistical framework that uses collisional evolution models, shock physics modeling and scaling laws to determine the range of plausible collisional histories for individual meteorite parent bodies. It is likely that those parent bodies that were not catastrophically disrupted sustained hundreds of impacts on their surfaces - compacting, heating, and mixing the outer layers; it is highly unlikely that many parent bodies escaped without any impacts processing the outer few kilometers. The first 10 - 20 Myr were the most important time for impacts, both in terms of the number of impacts and the increase of specific internal energy due to impacts. The model has been applied to evaluate the proposed impact histories of several meteorite parent bodies: up to 10 parent bodies that were not disrupted in the first 100 Myr experienced a vaporizing collision of the type necessary to produce the metal inclusions and chondrules on the CB chondrite parent; around 1 - 5% of bodies that were catastrophically disrupted after 12 Myr sustained impacts at times that match the heating events recorded on the IAB/winonaite parent body; more than 75% of 100 km radius parent bodies which survived past 100 Myr without being disrupted sustained an impact that excavates to the depth required for mixing in the outer layers of the H chondrite parent body; and to protect the magnetic field on the CV chondrite parent body, the crust would have had to have been thick (~ 20 km) in order to prevent it being punctured by impacts.

30 pages, 11 figures, 3 tables. Accepted for publication in Meteoritics & Planetary Science

References in corpus (6)

• A low mass for Mars from Jupiter's early gas-driven migration
• Towards planetesimals: dense chondrule clumps in the protoplanetary nebula
• Full Numerical Simulations of Catastrophic Small Body Collisions
• High Velocity Dust Collisions: Forming Planetesimals in a Fragmentation Cascade with Final Accretion
• Post-Impact Thermal Evolution of Porous Planetesimals
• Thermal history modeling of the H chondrite parent body

Cited by in corpus (14)

• The effects of short-lived radionuclides and porosity on the early thermo-mechanical evolution of planetesimals
• Thermal history modeling of the H chondrite parent body
• Thermal and Impact History of the H Chondrite Parent Asteroid during Metamorphism: Constraints from Metallic Fe-Ni
• Mesoscale Modeling of Impact Compaction of Primitive Solar System Solids
• Thermal history modeling of the L chondrite parent body
• The collisional evolution of undifferentiated asteroids and the formation of chondritic meteoroids
• Cosmic dust fertilization of glacial prebiotic chemistry on early Earth
• Collisional heating and compaction of small bodies: Constraints for their origin and evolution
• The Dissipation of the Solar Nebula Constrained by Impacts and Core Cooling in Planetesimals
• Global Scale Impacts
• High-Resolution Observations of Bright Boulders on Asteroid Ryugu: 2. Spectral Properties
• Thermal evolution and sintering of chondritic planetesimals IV. Temperature dependence of heat conductivity of asteroids and meteorites
• Metal-silicate mixing in planetesimal collisions
• Episodic planetesimal disruptions triggered by dissipation of gas disk