Supernova Propagation And Cloud Enrichment: A new model for the origin of $^{60}$Fe in the early solar system

TL;DR

This paper proposes a new model suggesting that the radioactive isotope $^{60}$Fe in the early solar system was inherited from multiple supernovae during molecular cloud formation, rather than from a single nearby supernova.

Contribution

It introduces a stochastic model estimating $^{60}$Fe abundance in star-forming regions, explaining its presence in the early solar system without requiring a single supernova event.

Findings

Many molecular clouds contain $^{60}$Fe at levels compatible with the early solar system.

Inheritance from multiple supernovae explains $^{60}$Fe presence without special events.

The model also accounts for $^{26}$Al abundance in star-forming regions.

Abstract

The radioactive isotope $^{60}$Fe ($T_{1/2} = 1.5 $ Myr) was present in the early solar system. It is unlikely that it was injected directly into the nascent solar system by a single, nearby supernova. It is proposed instead that it was inherited during the molecular cloud stage from several supernovae belonging to previous episodes of star formation. The expected abundance of $^{60}$Fe in star forming regions is estimated taking into account the stochasticity of the star-forming process, and it is showed that many molecular clouds are expected to contain $^{60}$Fe (and possibly $^{26}$Al [$T_{1/2} = 0.74 $ Myr]) at a level compatible with that of the nascent solar system. Therefore, no special explanation is needed to account for our solar system's formation.