Terrestrial Planet Formation From Lost Inner Solar System Material

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Terrestrial planet formation

Two fundamentally different processes of rocky planet formation exist, but it is unclear which one built the terrestrial planets of the solar system.

Either they formed by collisions among planetary embryos from the inner solar system, or by accreting sunward-drifting millimeter-sized 'pebbles' from the outer solar system. We show that the isotopic compositions of Earth and Mars are governed by two-component mixing among inner solar system materials, including material from the innermost disk unsampled by meteorites, whereas the contribution of outer solar system material is limited to a few percent by mass.

This refutes a pebble accretion origin of the terrestrial planets, but is consistent with collisional growth from inner solar system embryos. The low fraction of outer solar system material in Earth and Mars indicates the presence of a persistent dust-drift barrier in the disk, highlighting the specific pathway of rocky planet formation in the solar system.

Christoph Burkhardt, Fridolin Spitzer, Alessandro Morbidelli, Gerrit Budde, Jan H. Render, Thomas S. Kruijer, Thorsten Kleine

Comments: combined main test + supplement of published article
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Journal reference: Science Advances 7, 52, abj7601 (2021)
DOI: 10.1126/sciadv.abj7601
Cite as: arXiv:2201.08092 [astro-ph.EP] (or arXiv:2201.08092v1 [astro-ph.EP] for this version)
Submission history
From: Christoph Burkhardt
[v1] Thu, 20 Jan 2022 09:44:53 UTC (1,415 KB)
https://arxiv.org/abs/2201.08092
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