# Galactic Archaeology with [Mg/Mn] versus [Al/Fe] abundance ratios -- Uncertainties and caveats

**Authors:** Arianna Vasini, Emanuele Spitoni, Francesca Matteucci  
**arXiv:** [2310.04530](https://arxiv.org/abs/2310.04530)  
**Date:** 2023-10-06  
**Summary page:** https://www.summarizepaper.com/en/paper/2310.04530v1/

## Key points

- The abundance ratios [Mg/Mn] vs. [Al/Fe] are used to study the evolution of the Milky Way and the Local Group
- These ratios reflect the imprints left by different nucleosynthesis processes on elemental abundances
- Uncertainties associated with these abundance ratios make it challenging to assess their reliability
- Vasini et al. analyze nuclear uncertainties of Mg, Al, Mn, and Fe using chemical evolution models
- Different yield assumptions can affect these abundance ratios and undermine their diagnostic power for inferring star formation histories (SFHs)
- Existing literature yields require corrective factors to accurately reproduce APOGEE DR17 abundances in the Milky Way and Large Magellanic Cloud (LMC)
- Modifying massive star yields of Mg and Al significantly alters the behavior of the [Mg/Mn] vs. [Al/Fe] plot
- Different yield assumptions lead to divergent trends in this diagram, making it difficult to draw reliable conclusions about galaxy SFHs
- Reduction of uncertainties in nucleosynthesis calculations through future stellar studies may improve the reliability of this diagram as a diagnostic tool for SFHs

## Summary

The abundance ratios [Mg/Mn] vs. [Al/Fe] have been widely studied in recent literature as a valuable tool for investigating the evolution of the Milky Way and the Local Group. These ratios are believed to be highly sensitive to the star formation history (SFH) of galaxies, as they reflect the imprints left by different nucleosynthesis processes on elemental abundances. However, a comprehensive discussion on the uncertainties associated with these abundance ratios is still lacking, which makes it challenging to assess the reliability of the results obtained using this diagnostic. In this study, Vasini et al. utilize detailed chemical evolution models to analyze the nuclear uncertainties of Mg, Al, Mn, and Fe and their impact on the trends observed in the [Mg/Mn] vs. [Al/Fe] plane. The authors investigate how different yield assumptions can affect these abundance ratios and whether conflicting results from different yield models undermine the diagnostic power of this diagram for inferring SFHs. The authors discuss their findings based on various Milky Way (MW) and Large Magellanic Cloud (LMC) chemical evolution models that adopt different nucleosynthesis prescriptions. They find that existing literature yields require some corrective factors to accurately reproduce the APOGEE DR17 abundances of Mg, Al, and Mn in the MW. Interestingly, these same corrective factors also improve results for the LMC. Specifically, modifying massive star yields of Mg and Al significantly alters the behavior of the [Mg/Mn] vs. [Al/Fe] plot. Overall, by considering uncertainties within their error bars, Vasini et al demonstrate that different yield assumptions lead to divergent trends in this diagram making it difficult to draw reliable conclusions about galaxy SFHs. Consequently they conclude that while this diagram has potential as a diagnostic tool for SFHs if uncertainties in nucleosynthesis calculations can be reduced through future stellar studies; at present it remains uncertain from a theoretical standpoint.