Rocky Planetesimal Formation via Fluffy Aggregates of Nanograins

Abstract

Several pieces of evidence suggest that silicate grains in primitive meteorites are not interstellar grains but condensates formed in the early solar system. Moreover, the size distribution of matrix grains in chondrites implies that these condensates might be formed as nanometer-sized grains. Therefore, we propose a novel scenario for rocky planetesimal formation in which nanometer-sized silicate grains are produced by evaporation and recondensation events in early solar nebula, and rocky planetesimals are formed via aggregation of these nanograins. We reveal that silicate nanograins can grow into rocky planetesimals via direct aggregation without catastrophic fragmentation and serious radial drift, and our results provide a suitable condition for protoplanet formation in our solar system.

6 pages, 1 figure. Accepted for publication in ApJ Letters

References in corpus (3)

• Particle Stirring in Turbulent Gas Disks: Including Orbital Oscillations
• Closed-form expressions for particle relative velocities induced by turbulence
• Revisiting Jovian-Resonance Induced Chondrule Formation

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• Compound chondrule formation in optically thin shock waves
• Dynamics of Porous Dust Aggregates and Gravitational Instability of Their Disk
• Nonlinear Outcome of Coagulation Instability in Protoplanetary Disks II: Dust Ring Formation Mediated by Backreaction and Fragmentation
• Ejection of Chondrules from Fluffy Matrices
• Aggregate Growth and Internal structures of Chondrite Parent Bodies Forming from Dense Clumps