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The origin of carbon in the Universe - insights from observations of metal-poor stars in Magellanic Clouds

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Author(s):
Tiago Mendes de Almeida
Total Authors: 1
Document type: Master's Dissertation
Press: São Paulo.
Institution: Universidade de São Paulo (USP). Instituto Astronômico e Geofísico (IAG/SBD)
Defense date:
Examining board members:
Silvia Cristina Fernandes Rossi; Timothy Carter Beers; Marcos Perez Diaz
Advisor: Silvia Cristina Fernandes Rossi
Abstract

This project searches for signs of correlation between metallic stellar content, available for the Milky Way, and the metallicities indices obtained for the Magellanic Clouds. This comparison is supported by the traces on the formation of these three galaxies, that should have been left by each triplet members encounter. Since these crosses depend on the dynamical history, their fingerprints left by stellar content can estabilish constraints to the Galactic dynamical history. Spectroscopic data for a sample of carbon stars, obtained on the Magellanic Telescope, are used in this work. The amount of carbon, as the existence or not of binary stars in this sample, indicates possible sources of this element. The determination of sample properties is essential for studying the constraints between two stellar populations that are apparently distincts: carbon stars and carbon enhanced metal-poor stars. To do this, spectral catalogues and photometric criteria are used. Finding the correlations between both populations will bring some light to the unknown carbon enrichment processes that occured at the stellar atmospheres. Variability, emission lines, and binarity are studied for the sample. Stellar parameters are discussed, although there is no method applicable to this sample. By estimating the physical parameters of the stars presented in this sample and by analysing their carbon abundances, one can provide hints of the star formation history of objects in the Magellanic Clouds and therefore constraint the evolution of these satellite-galaxies to the Milky Way. (AU)