Fingerprints of the protosolar cloud collapse in the Solar System II: Nucleosynthetic anomalies in meteorites

TL;DR

This study models the collapse of the protosolar cloud, revealing how initial isotopic heterogeneity was preserved in meteorites and influenced by their formation location and thermal processing.

Contribution

It provides a model linking protosolar cloud collapse to isotopic heterogeneity in meteorites, highlighting the preservation of nucleosynthetic signatures.

Findings

Solid-weighted standard deviation of nucleosynthetic contributions is reduced in the disk.

Enrichment of r-process components in carbonaceous chondrites supports formation at large heliocentric distances.

Thermal processing had little effect on isotopic composition of refractory elements.

Abstract

The isotopic heterogeneity of the Solar System shown by meteorite analyses is more pronounced for its earliest objects, the Calcium-Aluminum-rich Inclusions (CAIs). This suggests that it was inherited from spatial variations in different stardust populations in the protosolar cloud. We model the formation of the solar protoplanetary disk following its collapse and find that the solid-weighted standard deviation of different nucleosynthetic contributions in the disk is reduced by one order of magnitude compared to the protosolar cloud, whose successive isotopic signatures are fossilized by CAIs. The enrichment of carbonaceous chondrites in r-process components, whose proportions are inferred to have diminished near the end of infall, is consistent with their formation at large heliocentric distances, where the early signatures would have been preferentially preserved after outward advection. We also argue that thermal processing had little effect on the (mass-independent) isotopic composition of bulk meteorites for refractory elements.