FCE - Trabajos de Titulación Post-Grado

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Examinando FCE - Trabajos de Titulación Post-Grado por Autor "Caffau, Elisabetta"

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    Sulfur abundances in the milky way major components
    (Universidad Andrés Bello, 2023) Lucertini, Francesca; Monaco, Lorenzo; Caffau, Elisabetta; Sbordone, Luca; Bonifacio, Piercarlo; Francois, Patrick; Facultad de Ciencias Exactas
    The measurements of chemical abundances and their ratios are a powerful diagnostic to put con straints on both stellar nucleosynthesis and galaxy formation history. For instance, the ratio between elements produced on different timescales, such as α-elements (produced by Supernovae Type-II after ∼30 Myr) and iron (produced by Supernovae Type-Ia on longer timescales), can be used as cosmic clocks. Sulfur is an α-element produced in the final stage of the evolution of massive stars by oxygen convective shell burning and explosive oxygen burning. Moreover, it is moderately volatile so, unlike other α-elements, its abundance measured in stars in the Local Group galaxies can be directly compared to the abundance measured in the gaseous phase in the far Universe, as extra-galactic H II regions or damped Ly-α systems. For these reasons sulfur abundances provide clues on star forma tion history and properties of the interstellar medium, connecting the local and distant Universe. Despite the great potential of this element, most of the available stellar abundances of sulfur come from Galactic stars. Only in the latest years, this analysis was expanded to stars outside the Milky Way. Our view of the behavior of Sulphur in the Milky Way and its satellite is, thus, far from complete. I ran a series of experiments to define the top level requirements needed to measure sulfur abun dances, and I explored the ESO archive looking for available data in a setup adequate for my goal. I identified several interesting public datasets. I focused on the Milky Way major components and, in particular, I found useful data for the Galactic bulge and disk, and a few clusters likely residual of accretion events in the Milky Way (like ω Cen, M 54 and Rup 106). Furthermore, the collaboration with the MINCE project gave me access to high-quality spectra of giant stars at intermediate metallicities in the Milky Way halo. The analysis of this dataset provides important clues about the evolution of Sulphur within the Milky Way. It provides a homogeneous database useful to compare the Milky Way major components with distant systems.