Accretion of the earliest inner solar system planetesimals beyond the water-snowline

Fuente: arXiv
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Autores principales: Grewal, Damanveer S., Nie, Nicole X., Zhang, Bidong, Izidoro, Andre, Asimow, Paul D.
Formato: Preprint
Publicado: 2024
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author Grewal, Damanveer S.
Nie, Nicole X.
Zhang, Bidong
Izidoro, Andre
Asimow, Paul D.
author_facet Grewal, Damanveer S.
Nie, Nicole X.
Zhang, Bidong
Izidoro, Andre
Asimow, Paul D.
contents How and where the first generation of inner solar system planetesimals formed remains poorly understood. Potential formation regions are the silicate condensation line and water-snowline of the solar protoplanetary disk. Whether the chemical compositions of these planetesimals align with accretion at the silicate condensation line (water-free and reduced) or water-snowline (water-bearing and oxidized) is, however, unknown. Here we use Fe/Ni and Fe/Co ratios of magmatic iron meteorites to quantify the oxidation states of the earliest planetesimals associated with non-carbonaceous (NC) and carbonaceous (CC) reservoirs, representing the inner and outer solar system, respectively. Our results show that the earliest NC planetesimals contained substantial amounts of oxidized Fe in their mantles (3-19 wt% FeO). In turn, we argue that this required the accretion of water-bearing materials into these NC planetesimals. The presence of substantial quantities of moderately and highly volatile elements in their parent cores is also inconsistent with their accretion at the silicate condensation line and favors instead their formation at or beyond the water-snowline. Similar oxidation states in the early-formed parent bodies of NC iron meteorites and those of NC achondrites and chondrites with diverse accretion ages suggests that the formation of oxidized planetesimals from water-bearing materials was widespread in the early history of the inner solar system.
format Preprint
id arxiv_https___arxiv_org_abs_2408_17032
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Accretion of the earliest inner solar system planetesimals beyond the water-snowline
Grewal, Damanveer S.
Nie, Nicole X.
Zhang, Bidong
Izidoro, Andre
Asimow, Paul D.
Earth and Planetary Astrophysics
How and where the first generation of inner solar system planetesimals formed remains poorly understood. Potential formation regions are the silicate condensation line and water-snowline of the solar protoplanetary disk. Whether the chemical compositions of these planetesimals align with accretion at the silicate condensation line (water-free and reduced) or water-snowline (water-bearing and oxidized) is, however, unknown. Here we use Fe/Ni and Fe/Co ratios of magmatic iron meteorites to quantify the oxidation states of the earliest planetesimals associated with non-carbonaceous (NC) and carbonaceous (CC) reservoirs, representing the inner and outer solar system, respectively. Our results show that the earliest NC planetesimals contained substantial amounts of oxidized Fe in their mantles (3-19 wt% FeO). In turn, we argue that this required the accretion of water-bearing materials into these NC planetesimals. The presence of substantial quantities of moderately and highly volatile elements in their parent cores is also inconsistent with their accretion at the silicate condensation line and favors instead their formation at or beyond the water-snowline. Similar oxidation states in the early-formed parent bodies of NC iron meteorites and those of NC achondrites and chondrites with diverse accretion ages suggests that the formation of oxidized planetesimals from water-bearing materials was widespread in the early history of the inner solar system.
title Accretion of the earliest inner solar system planetesimals beyond the water-snowline
topic Earth and Planetary Astrophysics
url https://arxiv.org/abs/2408.17032