An early giant planet instability recorded in asteroidal meteorites

TL;DR

This study uses meteorite thermochronology data and thermal modeling to date a giant planet instability in our solar system, linking it to the dissipation of the protoplanetary disk approximately 11 million years after Sun formation.

Contribution

It provides the first quantitative constraint on the timing of giant planet instability using asteroid meteorite thermochronology and advanced thermal modeling.

Findings

Giant planet instability occurred around 11 million years after Sun formation.

Meteorite age distribution supports a significant bombardment event linked to planetary migration.

The instability is associated with the dissipation of the gaseous protoplanetary disk.

Abstract

Giant planet migration appears widespread among planetary systems in our Galaxy. However, the timescales of this process, which reflect the underlying dynamical mechanisms, are not well constrained, even within the solar system. Since planetary migration scatters smaller bodies onto intersecting orbits, it would have resulted in an epoch of enhanced bombardment in the solar system's asteroid belt. To accurately and precisely quantify the timescales of migration, we interrogate thermochronologic data from asteroidal meteorites, which record the thermal imprint of energetic collisions. We present a database of 40K-40Ar system ages from chondrite meteorites and evaluate it with an asteroid-scale thermal code coupled to a Markov chain Monte Carlo inversion. Simulations require bombardment in order to reproduce the observed age distribution and identify a bombardment event beginning 11.3 +9.5/-6.6 million years after the Sun formed (50% credible interval). Our results associate a giant planet instability in our solar system with the dissipation of the gaseous protoplanetary disk.