Dynamical evolution of the Earth–Moon progenitors – Whence Theia?

2014/10/27 by Billy Quarles, Jack J. Lissauer · 25 citations
Earth and Planetary Sciences · Physics and Astronomy · #Astro and Planetary Science #Astrobiology #Astronomy #Geology and Paleoclimatology Research #Giant planet #Physics #Planet #Planetary Science and Exploration #Planetary system #Solar System #Terrestrial planet #Venus #astro-ph.EP

paper · pdf · doi:10.1016/j.icarus.2014.10.044

published in Icarus 248, 318-339 (Elsevier BV) · 17 pages, Accepted for publication in Icarus

arxiv created 2014/10/27 · openalex publication_date 2014/11/10 · arxiv updated 2014/12/03 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05

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.

Citations

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