Dynamical Evolution of the Earth-Moon Progenitors - Whence Theia?

Abstract

We present integrations of a model Solar System with five terrestrial planets (beginning ~30-50 Myr after the formation of primitive Solar System bodies) in order to determine the preferred regions of parameter space leading to a giant impact that resulted in the formation of the Moon. Our results indicate which choices of semimajor axes and eccentricities for Theia (the proto-Moon) at this epoch can produce a late Giant Impact, assuming that Mercury, Venus, and Mars are near the current orbits. We find that the likely semimajor axis of Theia, at the epoch when our simulations begin, depends on the assumed mass ratio of Earth-Moon progenitors (8/1, 4/1, or 1/1). The low eccentricities of the terrestrial planets are most commonly produced when the progenitors have similar semimajor axes at the epoch when our integrations commence. Additionally, we show that mean motion resonances among the terrestrial planets and perturbations from the giant planets can affect the dynamical evolution of the system leading to a late Giant Impact.

17 pages, Accepted for publication in Icarus

References in corpus (5)

• Dynamics of the giant planets of the solar system in the gaseous proto-planetary disk and relationship to the current orbital architecture
• Highly Siderophile Elements in the Earth's Mantle as a Clock for the Moon-forming Impact
• Lunar and Terrestrial Planet Formation in the Grand Tack Scenario
• Formation and accretion history of terrestrial planets from runaway growth through to late time: implications for orbital eccentricity
• On the origin and composition of Theia: Constraints from new models of the Giant Impact

Cited by in corpus (12)

• The Feeding Zones of Terrestrial Planets and Insights into Moon Formation
• Solar System Physics for Exoplanet Research
• Constraints on the pre-impact orbits of Solar System giant impactors
• Dynamical Constraints on Mercury's Collisional Origin
• Collision Chains among the Terrestrial Planets. III. Formation of the Moon
• Oort cloud asteroids: Collisional evolution, the Nice Model, and the Grand Tack
• Explaining Mercury via a single giant impact is highly unlikely
• Can a jumping-Jupiter trigger the Moon's formation impact?
• Rethinking the role of the giant planet instability in terrestrial planet formation models
• Mercury's formation within the Early Instability Scenario
• A formation pathway for terrestrial planets with moderate water content involving atmospheric-volatile recycling
• A pebble accretion model for the formation of the terrestrial planets in the Solar System