Impact splash chondrule formation during planetesimal recycling

Abstract

Chondrules are the dominant bulk silicate constituent of chondritic meteorites and originate from highly energetic, local processes during the first million years after the birth of the Sun. So far, an astrophysically consistent chondrule formation scenario, explaining major chemical, isotopic and textural features, remains elusive. Here, we examine the prospect of forming chondrules from planetesimal collisions. We show that intensely melted bodies with interior magma oceans became rapidly chemically equilibrated and physically differentiated. Therefore, collisional interactions among such bodies would have resulted in chondrule-like but basaltic spherules, which are not observed in the meteoritic record. This inconsistency with the expected dynamical interactions hints at an incomplete understanding of the planetary growth regime during the protoplanetary disk phase. To resolve this conundrum, we examine how the observed chemical and isotopic features of chondrules constrain the dynamical environment of accreting chondrite parent bodies by interpreting the meteoritic record as an impact-generated proxy of planetesimals that underwent repeated collision and reaccretion cycles. Using a coupled evolution-collision model we demonstrate that the vast majority of collisional debris feeding the asteroid main belt must be derived from planetesimals which were partially molten at maximum. Therefore, the precursors of chondrite parent bodies either formed primarily small, from sub-canonical aluminum-26 reservoirs, or collisional destruction mechanisms were efficient enough to shatter planetesimals before they reached the magma ocean phase. Finally, we outline the window in parameter space for which chondrule formation from planetesimal collisions can be reconciled with the meteoritic record and how our results can be used to further constrain early solar system dynamics.

20 pages, 11 figures, 2 tables; accepted for publication in Icarus; associated blog article at goo.gl/5bDqGC

References in corpus (13)

• Towards planetesimals: dense chondrule clumps in the protoplanetary nebula
• How to form planetesimals from mm-sized chondrules and chondrule aggregates
• Close-in planetesimal formation by pile-up of drifting pebbles
• Challenges in Planet Formation
• Full Numerical Simulations of Catastrophic Small Body Collisions
• Isotopic enrichment of forming planetary systems from supernova pollution
• The Asteroid Belt as a Relic From a Chaotic Early Solar System
• Forming chondrules in impact splashes. I. Radiative cooling model
• Thermal evolution and sintering of chondritic planetesimals II. Improved treatment of the compaction process
• Planetesimal collisions as a chondrule forming event
• A critical analysis of shock models for chondrule formation
• Onset of oligarchic growth and implication for accretion histories of dwarf planets
• Modeling gravitational instabilities in self-gravitating protoplanetary disks with adaptive mesh refinement techniques

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• Redox hysteresis of super-Earth exoplanets from magma ocean circulation
• Formation of Venus, Earth and Mars: Constrained by isotopes
• 53Mn-53Cr chronology and ε54Cr-Δ17O genealogy of Erg Chech 002: the oldest andesite in the Solar System
• Jetting during oblique impacts of spherical impactors
• Collisions and compositional variability in chondrule-forming events
• The Exosphere as a Boundary: Origin and Evolution of Airless Bodies in the Inner Solar System and Beyond Including Planets with Silicate Atmospheres
• Modification of icy planetesimals by early thermal evolution and collisions: Constraints for formation time and initial size of comets and small KBOs
• Streaming instability on different scales. I. Planetesimal mass distribution variability
• A Radiative Heating Model for Chondrule and Chondrite Formation
• Chondrule formation by collisions of planetesimals containing volatiles triggered by Jupiter's formation
• Spatial distribution of isotopes and compositional mixing in the inner protoplanetary disk
• Isotope velocimetry: Experimental and theoretical demonstration of the potential importance of gas flow for isotope fractionation during evaporation of protoplanetary material
• Chondrule Formation During Low-Speed Collisions of Planetesimals: A Hybrid Splash-Flyby Framework