Precise abundances of Mg and neutron-capture elements in the Milky Way: chemodynamical relations using Gaia data and chemical evolution models

Santos-Peral, Pablo; Recio-Blanco, Alejandra; de Laverny, Patrick; Palicio, Pedro A.; Fernández-Alvar, Emma
Bibliographical reference

EAS2024

Advertised on:
7
2024
Number of authors
5
IAC number of authors
1
Citations
0
Refereed citations
0
Description
The abundance of alpha and neutron-capture elements provide an important fossil signature in Galactic archaeology for tracing the chemical evolution of the Milky Way stellar populations. The combination with the astrometry and photometry from the Gaia data releases allow us to build an accurate time evolving chemodynamical picture of the Galaxy with unprecedented detail. We employ the automated abundance estimation procedure GAUGUIN, developed in the Gaia/RVS analysis pipeline, for deriving precise Mg, Eu and Sr abundances for stars observed by the ESO spectrographs HARPS (R ~ 115000), FEROS (R ~ 48000) and UVES (R ~ 40000), and parametrised within the AMBRE Project. With respect to the precise Mg abundances, we interpret the Galactic disc evolution by using Gaia astrometric measurements and estimating ages and dynamical properties for 366 main sequence turn-off (MSTO) stars in the solar neighbourhood. Our data favour the rapid formation of an early disc that settled in the inner regions, followed by the accretion of external metal-poor gas that may have triggered the formation of the thin disc population. A direct comparison with chemical evolution models also indicate that the infall in the inner Galactic regions was chemically enriched whereas a primordial infall should have formed the outer regions. On the other hand, we derive heavy element abundances (r-/s- process elements as Eu and Sr) for a sample of 778 Milky Way stars, homogeneously characterised using Gaia data, to chemically and dynamically identify potential accreted stellar populations and study their different signatures with respect to the in-situ population formed in the Galaxy. In agreement with previous works, r-process element enhancements have been observed in some metal-poor stars ([M/H] < -1.0 dex), turning them into a crucial key to investigate the early stages of the formation and chemical evolution of a galaxy.