A Magnetized, Moon-Forming Giant Impact

Abstract

The Moon is believed to have formed in the aftermath of a giant impact between a planetary mass body and the proto-Earth. In a typical giant impact scenario, a disk of vapor, liquid, and solid debris forms around the proto-Earth and--after possibly decades of evolution--condenses to form the Moon. Using state-of-the-art numerical simulations, we investigate the dynamical effects of magnetic fields on the Moon-forming giant impact. We show that turbulence generated by the collision itself, shear in the boundary layer between the post-impact debris field and the proto-Earth, and turbulence in the vapor component of the disk amplify the field to dynamically significant strengths. Magnetically driven turbulence promotes angular momentum transport in the protolunar disk. Debris material is accreted onto the proto-Earth, making Moon formation less efficient, while the disk is forced to spread to larger radii, cooling at its outer edge. Magnetic fields speed the evolution of the vapor component of the protolunar disk and hasten the formation of the Moon.

arXiv comment14 pages, 5 figures

References in corpus (18)

• A Multi-Code Analysis Toolkit for Astrophysical Simulation Data
• The Athena++ Adaptive Mesh Refinement Framework: Design and Magnetohydrodynamic Solvers
• The Magnetic Fields of Classical T Tauri Stars
• The origin of the Moon within a terrestrial synestia
• Efficient magnetic-field amplification due to the Kelvin-Helmholtz instability in binary neutron star mergers
• A hit-and-run Giant Impact scenario
• Multiple Impact Origin for the Moon
• High-Resolution Simulations of a Moon-Forming Impact and Post-Impact Evolution
• General relativistic simulations of binary black hole-neutron stars: Precursor electromagnetic signals
• Vapor drainage in the protolunar disk as the cause for the depletion in volatile elements of the Moon
• On the Origin of Earth's Moon
• Angular Momentum Transport by Acoustic Modes Generated in the Boundary Layer I: Hydrodynamical Theory and Simulations
• Supersonic Shear Instabilities in Astrophysical Boundary Layers
• Angular Momentum Transport and Variability in Boundary Layers of Accretion Disks Driven by Global Acoustic Modes
• A hot big bang theory: magnetic fields and the early evolution of the protolunar disk
• A Fast Poisson Solver of Second-Order Accuracy for Isolated Systems in Three-Dimensional Cartesian and Cylindrical Coordinates
• The role of multiple giant impacts in the formation of the Earth-Moon system
• Magneto-rotational instability in the protolunar disk

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• An Extension of the Athena++ Framework for Fully Conservative Self-Gravitating Hydrodynamics
• Composition, Structure and Origin of the Moon
• The Limited Role of the Streaming Instability During Moon and Exomoon Formation
• The "Drake equation" of exomoons -- a cascade of formation, stability and detection
• Towards Higher Order Accuracy in Self-Gravitating Hydrodynamics