Speaker
Description
The formation and evolution of the Milky Way has been a long-standing subject of interest. Stars in the thick and thin disc components overlap in the intermediate-age regime, unlike at the extreme ends of the metallicity versus alpha-abundance spectrum, where both populations are well separated. In this study, we introduce a new technique that utilises the [Na/Fe] versus stellar age relation to separate thick and thin disc stars more effectively than current methods, thereby enabling cleaner sample selection for Galactic studies. We investigate the super-solar increase in [Na/Fe] abundances observed in Galactic Archaeology with HERMES (GALAH) data and other datasets by examining the impact of different nucleosynthetic yields. Using the OMEGA+ galactic chemical evolution code, we model sodium enrichment in the super-Solar metallicity regime with a single set of star-formation parameters, exploring how abundance trends vary with different combinations of core-collapse supernovae (CC SNe), Type Ia supernovae (SNe Ia), and asymptotic giant branch (AGB) metallicity-dependent yields. Our results demonstrate that none of the tested yield tables reproduces the observed metallicity-dependent behaviour of [Na/Fe]. This finding has significant implications for Galactic studies and highlights the need for improved stellar yield prescriptions in nucleosynthesis models.
| Stream | Science or Engineering |
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