# Explaining the decrease in ISM lithium at super-solar metallicities in the solar vicinity

## TL;DR

This paper explains the observed decrease in lithium at super-solar metallicities in the solar vicinity by considering the effects of radial migration and mixed stellar populations, challenging previous interpretations requiring modified stellar yields.

## Contribution

It introduces a model incorporating radial migration and mixed populations to explain lithium trends, emphasizing the importance of migration in chemical evolution analyses.

## Key findings

- Migrated stars from inner regions explain lower lithium at high metallicities
- Radial migration impacts chemical evolution interpretations
- Li-depletion models are lacking for super-solar metallicity stars

## Abstract

We propose here that the lithium decrease at super-solar metallicities observed in high resolution spectroscopic surveys can be explained by the interplay of mixed populations, coming from the inner regions of the Milky Way disc. The lower lithium content of these stars is a consequence of inside-out disc formation, plus radial migration. In this framework, local stars with super-solar metallicities would have migrated to the solar vicinity and depleted their original lithium during their travel time. To arrive to such a result, we took advantage of the AMBRE catalog of lithium abundances combined with chemical evolution models which take into account the contribution to the lithium enrichment by different nucleosynthetic sources. A large proportion of migrated stars can explain the observed lower lithium abundance at super-solar metallicities. We stress that nowadays, there is no stellar model able to predict Li-depletion for such super-solar metallicity stars, and the Solar Li-depletion has to be assumed. In addition, it currently exists no solid quantitative estimate of the proportion of migrated stars in the Solar neighborhood and their travel time. Our results illustrate how important it is to properly include radial migration when comparing chemical evolution models to observations, and that in this case, the lithium decrease at larger metallicities does not necessarily imply that stellar yields have to be modified, contrary to previous claims in literature.