Chemical enrichment of the pre-solar cloud by supernova dust grains

TL;DR

This study demonstrates that supernova dust grains can efficiently deliver short-lived radioisotopes into the pre-solar cloud, providing a plausible explanation for their observed abundances in meteorites.

Contribution

It introduces a numerical model showing dust grains can penetrate and enrich the pre-solar cloud with SLRs, overcoming previous gas-phase mixing limitations.

Findings

Dust grains > 1 micron penetrate the cloud within 0.1 Myr.

Gas-phase SLR injection is slow due to hydrodynamical instabilities.

Dust destruction releases SLRs, enriching star-forming regions.

Abstract

The presence of short-lived radioisotopes (SLRs) in solar system meteorites has been interpreted as evidence that the solar system was exposed to a supernova shortly before or during its formation. Yet results from hydrodynamical models of SLR injection into the proto-solar cloud or disc suggest that gas-phase mixing may not be efficient enough to reproduce the observed abundances. As an alternative, we explore the injection of SLRs via dust grains as a way to overcome the mixing barrier. We numerically model the interaction of a supernova remnant containing SLR-rich dust grains with a nearby molecular cloud. The dust grains are subject to drag forces and both thermal and non-thermal sputtering. We confirm that the expanding gas shell stalls upon impact with the dense cloud and that gas-phase SLR injection occurs slowly due to hydrodynamical instabilities at the cloud surface. In contrast, dust grains of sufficient size (> 1 micron) decouple from the gas and penetrate into the cloud within 0.1 Myr. Once inside the cloud, the dust grains are destroyed by sputtering, releasing SLRs and rapidly enriching the dense (potentially star-forming) regions. Our results suggest that SLR transport on dust grains is a viable mechanism to explain SLR enrichment.