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Main Authors: Fang, Tong, Bi, Rongxi, Zhang, Hui, Zhou, You, Reinhardt, Christian, Deng, Hongping
Format: Preprint
Published: 2024
Subjects:
Online Access:https://arxiv.org/abs/2411.14709
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author Fang, Tong
Bi, Rongxi
Zhang, Hui
Zhou, You
Reinhardt, Christian
Deng, Hongping
author_facet Fang, Tong
Bi, Rongxi
Zhang, Hui
Zhou, You
Reinhardt, Christian
Deng, Hongping
contents The solar system planets are benchmarks for the planet formation theory. Yet two paradigms coexist for the four terrestrial planets: the prolonged collisional growth among planetesimals lasting $>100$ million years (Myr) and the fast formation via planetesimals accreting pebbles within 10 Myr. Despite their dramatic difference, we can hardly tell which theory is more relevant to the true history of the terrestrial planets' formation. Here, we show that the Moon's origin puts stringent constraints on the pebble accretion scenario, rendering it less favourable. In the pebble accretion model, the one-off giant impact between proto-Earth and Theia rarely (probability $<$ 1\textperthousand) occurs at the right timing and configuration for the Moon formation. Even if a potential impact happens by chance, giant impact simulations reveal perfect mixing between proto-Earth and Theia, leaving no room for the observed primordial Earth mantle heterogeneity and the compositional difference, though small, between Earth and the Moon. Thus, the Earth-Moon system along other terrestrial planets should preferably form from chaotic collisional growth in the inner solar system.
format Preprint
id arxiv_https___arxiv_org_abs_2411_14709
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle The Moon-forming Impact as a Constraint for the Inner Solar System's Formation
Fang, Tong
Bi, Rongxi
Zhang, Hui
Zhou, You
Reinhardt, Christian
Deng, Hongping
Earth and Planetary Astrophysics
The solar system planets are benchmarks for the planet formation theory. Yet two paradigms coexist for the four terrestrial planets: the prolonged collisional growth among planetesimals lasting $>100$ million years (Myr) and the fast formation via planetesimals accreting pebbles within 10 Myr. Despite their dramatic difference, we can hardly tell which theory is more relevant to the true history of the terrestrial planets' formation. Here, we show that the Moon's origin puts stringent constraints on the pebble accretion scenario, rendering it less favourable. In the pebble accretion model, the one-off giant impact between proto-Earth and Theia rarely (probability $<$ 1\textperthousand) occurs at the right timing and configuration for the Moon formation. Even if a potential impact happens by chance, giant impact simulations reveal perfect mixing between proto-Earth and Theia, leaving no room for the observed primordial Earth mantle heterogeneity and the compositional difference, though small, between Earth and the Moon. Thus, the Earth-Moon system along other terrestrial planets should preferably form from chaotic collisional growth in the inner solar system.
title The Moon-forming Impact as a Constraint for the Inner Solar System's Formation
topic Earth and Planetary Astrophysics
url https://arxiv.org/abs/2411.14709