Giant impacts stochastically change the internal pressures of terrestrial planets

Abstract

Pressure is a key parameter in the physics and chemistry of planet formation and evolution. Previous studies have erroneously assumed that internal pressures monotonically increase with the mass of a body. Using smoothed particle hydrodynamics and potential field method calculations, we demonstrate that the hot, rapidly-rotating bodies produced by giant impacts can have much lower internal pressures than cool, slowly-rotating planets of the same mass. Pressures subsequently increase due to thermal and rotational evolution of the body. Using the Moon-forming impact as an example, we show that the internal pressures after the collision could have been less than half that in present-day Earth. The current pressure profile was not established until Earth cooled and the Moon receded, a process that may take up to 10s Myr after the last giant impact. Our work defines a new paradigm for pressure evolution during accretion of terrestrial planets: stochastic changes driven by impacts.

Main text: 23 pages, 6 figures. Supplementary material: 10 pages, 8 figures. Published in Science Advances

References in corpus (3)

• Melting and Mixing States of the Earth's Mantle after the Moon-Forming Impact
• Multiple Impact Origin for the Moon
• The structure of terrestrial bodies: Impact heating, corotation limits and synestias

Cited by in corpus (8)

• Super-Earths and Earth-like Exoplanets
• The energy budget and figure of Earth during recovery from the Moon-forming giant impact
• The Effect of Inefficient Accretion on Planetary Differentiation
• The Role of Giant Impacts in Planet Formation
• Effect of Equation of State and Cutoff Density in Smoothed Particle Hydrodynamics Simulations of the Moon-Forming Giant Impact
• The "Drake equation" of exomoons -- a cascade of formation, stability and detection
• Planets or asteroids? A geochemical method to constrain the masses of White Dwarf pollutants
• The energy budgets of giant impacts