2019MNRAS.483.1674R

We present the abundances analysis for a sample of 11 red giant branch stars in the metal-poor globular cluster NGC 6809 based on high-resolution spectra. Our main goals are to characterize its chemical composition and analyse this cluster's behaviour associated with the Multiple Populations (MPs) phenomenon. In our work, we obtained the stellar parameters and chemical abundances of 24 elements (O, Na, Mg, Al, Si, Ca, Ti, V, Cr, Mn, Fe, Co, Sc, Ni, Cu, Zn, Y, Zr, Ba, La, Ce, Eu, Nd, and Dy). We found a radial velocity of 174.7 ± 3.2 km s^–1 and a mean iron content of [Fe/H] = -2.01 ± 0.02 in good agreement with other studies. Moreover, we found a large spread in the abundances of the light elements O, Na, and Al confirming the presence of an Na-O anticorrelation or an Na-Al correlation. The Mg-Al anticorrelation is also present in our cluster. The α and iron-peak elements show good agreement with the halo field star trend. The heavy elements are dominated by the r-process.