Abundâncias de Elementos Bioessenciais em Estrelas de Tipo Solar usando Espectros HARPS

Abstract

Since the discovery of the first exoplanet around a solar-type star in 1995, we have witnessed a fast increase in the number of detected exoplanets – surpassing the mark of 5000. These discoveries, associated with an increasingly detailed characterization of exoplanets and their host stars, have expanded the frontiers of Astrobiology and allowed even more comprehensive studies on the formation and habitability of planets and the distribution of life in the Universe. When we think about life as we know it, we are naturally driven to think of the most frequent elements in the composition of organisms: the CHNOPS (carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur). Though they are bio-essential elements for life on Earth, they are not widely explored in abundance studies in general due to challenges in their analyses. Thus, for a better understanding of the structures of planets, habitability and life, it is fundamental to have more homogeneous and precise abundances for these elements for a large number of stars. Therefore, in this work, we derived abundances of C, O and S using equivalent widths measured on high quality HARPS spectra and the software MOOG, focusing on solar-type stars with detected exoplanets, in order to investigate the possible relation between these elements and the formation and habitability of planets, to contribute for a better understanding of the necessary conditions for life to emerge. Our homogeneous abundances will also contribute to the expansion and update of the Hypatia Catalog, allowing studies in other areas, such as chemical evolution of the Galaxy. We present results for abundances of Fe, C, O, Ni and S for 252 solar-type stars, for which we found good agreements with the literature. For a significance level of 0.02, we were able to distinguish host and non-host stars through the abundance of Fe, a result that is compatible with the literature.