Chemical Abundance Scale of Giant and Dwarf Stars

When comparing chemical abundances of main-sequence and evolved stars it is assumed that they share the same scale. Differences in the abundances of these stars are found and, if real, they have important consequences for planet formation theories and chemical evolution of the Galaxy. Thus, it is crucial to investigate whether the metallicity discrepancy between dwarfs and giants is real or produced by systematic errors in the analysis. In this conference, we present the preliminary test to establish a reliable abundance scale to be used in for both giant and dwarf stars. To achieve that, we selected stars of Hyades open cluster assuming that they share the same chemical composition. The giant stars of this cluster have both (i) high resolution spectroscopic database from HARPS, and (ii) direct measurements of the angular diameter by interferometry. We aim to perform a 1D-LTE spectroscopic analysis associated with a benchmark test to investigate the relevance of non-LTE effects. Herein, we show the preliminary test applied for the giant stars.