The nucleosynthetic fingerprint of the outermost protoplanetary disk and early Solar System dynamics

TL;DR

This study uncovers preserved outer protoplanetary disk material in a meteorite, revealing its origin in the comet-forming region and its widespread influence on outer Solar System bodies, challenging previous assumptions.

Contribution

It provides the first direct evidence of outer disk material in a meteorite and links it to the comet-forming region, highlighting late accretion processes in Solar System formation.

Findings

Outer disk material is preserved in a meteorite.

Outer disk material originated in the comet-forming region.

Outer Solar System bodies share a common nucleosynthetic signature.

Abstract

Knowledge of the nucleosynthetic isotope composition of the outermost protoplanetary disk is critical to understand the formation and early dynamical evolution of the Solar System. We report the discovery of outer disk material preserved in a pristine meteorite based on its chemical composition, organic-rich petrology, and 15N-rich, deuterium-rich, and 16O-poor isotope signatures. We infer that this outer disk material originated in the comet-forming region. The nucleosynthetic Fe, Mg, Si and Cr compositions of this material reveal that, contrary to current belief, the isotope signature of the comet-forming region is ubiquitous amongst outer Solar System bodies, possibly reflecting an important planetary building block in the outer Solar System. This nucleosynthetic component represents fresh material added to the outer disk by late accretion streamers connected to the ambient molecular cloud. Our results show that most Solar System carbonaceous asteroids accreted material from the comet-forming region, a signature lacking in the terrestrial planet region.