Early formation of planetary building blocks inferred from Pb isotopic ages of chondrules

TL;DR

This study uses Pb isotopic dating of chondrules to show that their primary formation occurred within the first million years of the solar system, supporting rapid planetary formation via chondrule accretion.

Contribution

It provides new chronological evidence that primary chondrule formation was confined to early solar system, with subsequent recycling, informing models of planet formation.

Findings

Primary chondrule formation occurred within the first million years.

Chondrules were recycled throughout the protoplanetary disk's lifetime.

Early abundance of chondrules facilitated rapid planetary accretion.

Abstract

The most abundant components of primitive meteorites (chondrites) are millimeter-sized glassy spherical chondrules formed by transient melting events in the solar protoplanetary disk. Using Pb-Pb dates of 22 individual chondrules, we show that primary production of chondrules in the early solar system was restricted to the first million years after formation of the Sun and that these existing chondrules were recycled for the remaining lifetime of the protoplanetary disk. This is consistent with a primary chondrule formation episode during the early high-mass accretion phase of the protoplanetary disk that transitions into a longer period of chondrule reworking. An abundance of chondrules at early times provides the precursor material required to drive the efficient and rapid formation of planetary objects via chondrule accretion.