The role of radial migration on tracing lithium evolution in the Galactic disk

TL;DR

This study investigates how radial migration affects lithium evolution in the Galactic disk, revealing that stars' birthplaces influence lithium abundance patterns and that migration must be considered in chemical evolution models.

Contribution

It demonstrates the significant impact of stellar radial migration on lithium abundance trends and aligns observational data with chemical evolution models across different galactic radii.

Findings

Stars in the solar neighborhood originate from various galactic radii.

The upper envelope of Li abundance varies with birth radius, explaining Li decrease in super-metal-rich stars.

Stars younger than 3 Gyr show less lithium depletion, matching theoretical predictions.

Abstract

With the calculated guiding center radius $R_{guiding}$ and birth radius $R_{birth}$, we investigate the role of radial migration on the description of lithium evolution in the Galactic disk based on the upper envelope of the A(Li) vs. [Fe/H] diagram. Using migration distances, we find that stars in the solar neighborhood are born at different locations in the galactic disk, and cannot all be explained by models of chemical evolution in the solar neighborhood. It is found that the upper envelope of the A(Li) vs. [Fe/H] diagram varies significantly with $R_{birth}$, which explains the decrease of Li for super-metal-rich (SMR) stars because they are non-young stars born in the inner disk. The upper envelope of Li-$R_{birth}$ plane fits very well with chemical evolution models by Grisoni et al. for $R_{birth} = 7 - 12$ kpc, outside which young stars generally lack sufficient time to migrate to the solar neighborhood. For stars born in the solar neighborhood, the young open clusters and the upper envelope of field stars with age $<$ 3 Gyr fit well with theoretical prediction. We find that calculations using stars with ages less than 3 Gyr are necessary to obtain an undepleted Li upper envelope, and that stars with solar age (around 4.5 Gyr) have depleted around 0.3 dex from the original value based on the chemical evolution model of Grisoni et al.