Carving Out the Inner Edge of the Period Ratio Distribution through Giant Impacts

2025/01/29 by Kaitlyn Chen, Oswaldo Cardenas, Chen, Kaitlyn +7
Biochemistry, Genetics and Molecular Biology · Earth and Planetary Sciences · Physics and Astronomy · #Astro and Planetary Science #Earth and Planetary Astrophysics (astro-ph.EP) #FOS: Physical sciences #Geology and Paleoclimatology Research #Geomagnetism and Paleomagnetism Studies

paper · pdf · doi:10.48550/arxiv.2501.17359

openalex publication_date 2025/01/29 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28

Abstract

The distribution of orbital period ratios between adjacent observed exoplanets is approximately uniform, but exhibits a strong falloff toward close orbital separations. We show that this falloff can be explained through past dynamical instabilities carving out the period ratio distribution. Our suite of numerical experiments would have required ∼ 3 million CPU-hours through direct N-body integrations, but was achieved with only ≈ 50 CPU-hours by removing unstable configurations using the Stability of Planetary Orbital Configurations Klassifier (SPOCK) machine learning model. This highlights the role of dynamical instabilities in shaping the observed exoplanet population, and shows that the inner part of the period ratio distribution provides a valuable observational anchor on the giant impact phase of planet formation.

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