Presolar grains

TL;DR

Presolar grains are ancient extraterrestrial particles with unique isotopic signatures that provide insights into stellar processes, galactic chemical evolution, and the early history of the solar system.

Contribution

This review summarizes recent advances in analyzing presolar grains' isotopic and structural data to understand stellar nucleosynthesis and interstellar dust evolution.

Findings

Presolar grains reveal diverse stellar origins.

Isotopic compositions constrain stellar and galactic processes.

Insights into solar system formation from extraterrestrial materials.

Abstract

The chemical makeup of our solar system is a reflection of Galactic chemical evolution in the local interstellar medium (ISM) over the past ~9 Ga before the formation of the solar system. Although the incorporated ISM dust was mostly destroyed during the solar system formation, a small fraction of the ISM dust, known as presolar grains, is preserved in pristine extraterrestrial materials and identified through their exotic isotopic compositions, pointing to their formation in gas outflows or explosions of ancient stars. Since their stellar birth at more than 4.6 Ga, presolar grains have borne witness to a diverse array of astrophysical and cosmochemical processes. In this chapter, I will review recent progress in utilizing the isotopic and structural compositions of presolar grains to constrain physical mixing processes and dust formation in stars, stellar nucleosynthesis, ISM processes, and the origin and evolution of the solar system.