Análise espectroscópica em alta resolução de estrelas candidatas a estrelas de Bário

Abstract

Barium stars are G and K type stars that exhibit an overabundance of elements synthesized through the slow neutron capture process (s-process) in their atmospheres, along with characteristic spectral signatures of C2, CH, and CN molecules. This overabundance is notable because barium stars do not have the necessary physical conditions to synthesize s-process elements in their own cores. These elements, in turn, are formed by asymptotic giant branch (AGB) stars and transported to the surface of these objects during thermal pulses. Assuming the well-established binary scenario, the transfer of these elements to their binary companion, now a barium star, occurs through the mechanism of mass transfer. Chemically peculiar stars, such as barium stars, are objects of particular astrophysical interest. This is due to the fact that chemically peculiar stars can provide important tests and constraints for theoretical models of nucleosynthesis, through the abundance profiles exhibited in their atmospheres. Only a detailed chemical analysis is capable of providing increasingly complete abundance patterns. The objective of this work is to determine chemical abundances for 6 candidate barium stars and verify the classification of these stars as chemically peculiar stars, as previously reported in the literature. To achieve this, we investigated the abundances of the following elements: Sr, Y, Zr, Ce, Nd, Sm, Ni, and Rb. High-resolution spectra used for the analysis were obtained using GRACES (Gemini Remote Access to CFHT ESPaDOnS Spectrograph), with observations conducted at the Gemini North telescope, which has an 8-meter diameter. As a result, we observed overabundance of s-process elements in three stars of our sample, while for the other three, the abundance patterns were consistent with those of field giant stars in the Galaxy. abundances; nucleosynthesis – stars: chemically peculiar – stars: abundances.