SISTEMAS BINÁRIOS ESPECTROSCÓPICOS EM AGLOMERADOS ABERTOS: UM ESTUDO DE ABUNDÂNCIAS QUÍMICAS Autor:ANDRE ALVES RAMOS

Abstract

Open clusters are star systems gravitationally bound and distributed throughout the galactic disk. Since their distances and ages are well determined, they become important astrophysical laboratories and can be used as chemical tracers of the structure of the Galaxy on a large scale. Furthermore, a study of binary stars in these systems is extremely important to constrain nucleosynthesis processes, as a binary interaction can result in chemically peculiar stars (e.g., barium stars and lithium-rich giants). In this sense, we carried out a study of chemical abundances using high resolution spectroscopy for a sample of 21 spectroscopic binary red giant stars distributed in 13 open clusters, to investigate possible influences of binarity on the chemical composition of these objects: mass transfer events or non-Traditional mixing can happen in close binary systems like these. To determine the chemical abundances of the sample, it was also necessary to determine its atmospheric parameters, and we compared the effective temperature and spectroscopic surface gravity with photometric values. In our investigation, we discovered a new lithium-rich giant (NGC 6694-14) that may have gone through some planet or brown dwarf accretion event, which would also explain its anomalous rotation. If we observe high enrichment in elements of the s-process, we conclude that the analyzed binary systems do not show traces of white dwarfs that would have possibly given up mass to these objects. In addition, 06 stars in our sample did not have atmospheric parameters and chemical abundances determined, as they have contamination in the spectrum by a spectral type A star, being classified as candidates for Yellow Stragglers, objects poorly studied in the literature.