Timescales of Solar System Formation Based on Al-Ti Isotope Correlation by Supernova Ejecta

TL;DR

This study uses Al-Ti isotope correlation to refine the timing and environment of the supernova that influenced solar system formation, revealing heterogeneity in Al distribution and a supernova event about 1 Myr before solar system solids formed.

Contribution

It introduces a novel use of Al-Ti isotope correlation to calibrate Al-Mg chronometers and constrains the supernova's timing and proximity to the protosolar cloud.

Findings

Heterogeneity in 26Al distribution correlates with Ti isotope variation.

A >1 Myr gap between accretion ages of different chondrites.

Supernova occurred 20-30 pc from the protosolar cloud, ~0.94 Myr before solar system formation.

Abstract

The radioactive decay of short-lived 26Al to 26Mg has been used to estimate the timescales over which 26Al was produced in a nearby star and the protosolar disk evolved. The chronology commonly assumes that 26Al was uniformly distributed in the protosolar disk; however, this assumption is challenged by the discordance between the timescales defined by the Al-Mg and assumption-free Pb-Pb chronometers. We find that the 26Al heterogeneity is correlated with the nucleosynthetic stable Ti isotope variation, which can be ascribed to the non-uniform distribution of ejecta from a core-collapse supernova in the disk. We use the Al-Ti isotope correlation to calibrate variable 26Al abundances in Al-Mg dating of early solar system processes. The calibrated Al-Mg chronometer indicates a >1 Myr gap between parent body accretion ages of carbonaceous and non-carbonaceous chondrites. We further use the Al-Ti isotope correlation to constrain the timing and location of the supernova explosion, indicating that the explosion occurred at 20-30 pc from the protosolar cloud, 0.94 +0.25/-0.21 Myr before the formation of the oldest solar system solids. Our results imply that the Sun was born in association with a ~25 solar mass star.