Lithium as a probe of stellar and galactic physics

TL;DR

Lithium serves as a crucial diagnostic tool in astrophysics for understanding stellar evolution, Galactic history, and cosmology, with recent models and observations advancing our knowledge of its sources and distribution.

Contribution

The paper reviews current lithium observations and models, highlighting the role of stellar transport processes, novae as Li sources, and stellar radial migration in Galactic Li evolution.

Findings

Stellar models with chemical transport explain Li patterns across populations.

Novae are likely the main Galactic Li sources.

Radial migration influences Li evolution in the Milky Way.

Abstract

Lithium plays a unique role in astrophysics, as it is a powerful diagnostic for the physics and evolution of low-mass stars, Galactic archaeology, and cosmology. We review the Li observations in stars at different phases of their evolution, the strengths and the limitations of the current theoretical stellar models to explain the Li abundance data, our understanding of the Li sources and of the evolution of Li through- out the Galactic history. Key takeaways from the current state of the research in the field are: 1) Stellar evolution models accounting for fundamental transport processes of chemical species and angular momentum hold the promise of providing a common stellar Li depletion explanation to the Li abundance patterns observed in all Galactic stellar populations, including the dip and the plateau(s). 2) Novae are most probably the main source of Li in the Galaxy, on observational (but not yet theoretically established) grounds. 3) Radial migration of stars in the Galactic disk holds the key to understand many aspects of the Li evolution in the Milky Way.