VLT-UVES abundance analysis of four giants in NGC 6553
Résumé
Context: .Metal-rich globular clusters trace the formation of bulges. Abundance ratios in the metal-rich globular clusters such as NGC 6553 can constrain the formation timescale of the Galactic bulge.
Aims: .The purpose of this study is to determine the metallicity and elemental ratios in individual stars of the metal-rich bulge globular cluster NGC 6553.
Methods: .A detailed abundance analysis of four giants in NGC 6553 is carried out, based on optical high-resolution échelle spectra obtained with UVES at the ESO VLT-UT2 Kueyen telescope.
Results: .A metallicity [Fe/H] = -0.20 dex is derived, together with alpha-element enhancement of Mg and Si ([Mg/Fe] = 0.28, [Si/Fe] = 0.21), solar Ca and Ti ([Ca/Fe] = 0.05, [Ti/Fe] = -0.01), and a mild enhancement of the r-process element Eu with [Eu/Fe] = 0.10. A mean heliocentric radial velocity of -1.86 km s-1 is measured. We compare our results with previous investigations of the cluster.
Aims: .The purpose of this study is to determine the metallicity and elemental ratios in individual stars of the metal-rich bulge globular cluster NGC 6553.
Methods: .A detailed abundance analysis of four giants in NGC 6553 is carried out, based on optical high-resolution échelle spectra obtained with UVES at the ESO VLT-UT2 Kueyen telescope.
Results: .A metallicity [Fe/H] = -0.20 dex is derived, together with alpha-element enhancement of Mg and Si ([Mg/Fe] = 0.28, [Si/Fe] = 0.21), solar Ca and Ti ([Ca/Fe] = 0.05, [Ti/Fe] = -0.01), and a mild enhancement of the r-process element Eu with [Eu/Fe] = 0.10. A mean heliocentric radial velocity of -1.86 km s-1 is measured. We compare our results with previous investigations of the cluster.