High-resolution spectroscopy of the old open cluster Collinder 261: abundances of iron and other elements

¹ INAF – Osservatorio Astronomico di Bologna, via Ranzani 1, 40127 Bologna, Italy e-mail: carretta@pd.astro.it
² INAF – Osservatorio Astronomico di Padova, Vicolo dell'Osservatorio 5, 35122 Padova, Italy

Received: 14 February 2005
Accepted: 30 May 2005

Abstract

We present the analysis of high resolution spectra of six red giant stars in the old open cluster Collinder 261. Reddening values for individual stars, derived from the relation between colours and temperatures (deduced from our fully spectroscopic analysis) are consistent with previous determinations based on photometry. For this cluster we derive an iron abundance of . We also obtain the abundances of light metals (O, Na and Al), α-elements (Mg, Si, Ca, Ti), elements of the Fe-group (Sc, Cr, Mn, Co, Ni) and the neutron-capture element Ba. No intrinsic star-to-star scatter is present in any of these elements within our sample. We compare our findings with previous investigations on this cluster, discussing in detail differences in analysis methods and results.