Heterogeneous evolution of the galaxy and the origin of the short-lived nuclides in the early solar system

TL;DR

This paper models the distribution and origin of short-lived radionuclides in the Milky Way and early solar system, highlighting the role of heterogeneous galactic evolution and stellar contributions.

Contribution

It introduces a novel heterogeneous galactic chemical evolution model that links galaxy evolution with the origin of short-lived radionuclides in the solar system.

Findings

Heterogeneous models better explain radionuclide distribution in the galaxy.

Solar system likely formed in an environment contaminated by older stellar clusters.

Multiple stellar sources contributed to radionuclide inventory in the early solar system.

Abstract

We present galactic chemical evolution (GCE) models of the short-lived radionuclides (SLRs), 26Al, 36Cl, 41Ca, 53Mn and 60Fe, across the entire Milky Way galaxy. The objective is to understand the spatial and temporal distribution of the SLRs in the galaxy. The gamma-ray observations infer widespread distribution of 26Al and 60Fe across the galaxy. The signatures of the SLRs in the early solar system (ESS) are found in meteorites. We present homogeneous GCE simulation models for SLRs across the galaxy. We also develop a set of heterogeneous GCE models to understand the evolution of the galaxy within independent spatial grids of area, 0.1-1 kpc2. These grids evolve distinctly in terms of nucleosynthetic contributions of massive stars. We succeeded in simulating the formation and evolution of generations of stellar clusters/association. Based on the formulation, we provide a novel method to amalgamate the origin of the solar system with the gradual evolution of the galaxy along with a self-consistent origin of SLRs. We explore the possibility of the birth of the solar system in an environment where one of the stellar clusters formed >25 Million years earlier. The decaying 53Mn and 60Fe remnants from the evolved massive stars from the cluster probably contaminated the local medium associated with the presolar molecular cloud. A Wolf-Rayet wind from a distant massive star, belonging to a distinct cluster, probably contributed, 26Al (and 41Ca) to the presolar cloud. The irradiation production of 7,10Be and 36Cl occurred later in ESS.