Metallicity of the star III-17 in the bulge globular cluster NGC 6553

Abstract

CCD échelle spectra were obtained at the 3.6 m telescope at ESO for the star III-17 of the metal-rich globular cluster NGC 6553. This cluster was chosen because it is a relatively dose bulge globular cluster and also it presented the possibility to be among the most metal-rich ones in the Galaxy. The metallicity of the star III-17 is derived by fitting synthetic spectra to the spectrum observed in the wavelength region λλ475–580 nm. We derived an overall metallicity of [M/H] = –0.2⁺⁰’²₋₀‚₄ , therefore approximately solar, whereas there may be an evidence for a CNO overabundance. Further observations of individual stars in NGC 6553 are necessary in order to definitely establish its metallicity.