The chemical composition of the stellar cluster Gaia1: no surprise behind Sirius

Abstract

We observed 6 He-clump stars of the intermediate-age stellar cluster Gaia1 with the MIKE/MAGELLAN spectrograph. A possible extra-galactic origin of this cluster, recently discovered thanks to the first data release of the ESA Gaia mission, has been suggested, based on its orbital parameters. Abundances for Fe, alpha, proton- and neutron-capture elements have been obtained. We find no evidence of intrinsic abundance spreads. The iron abundance is solar ([FeI/H]=+0.00 +-0.01; sigma = 0.03 dex). All the other abundance ratios are, by and large, solar-scaled, similar to the Galactic thin disk and open clusters stars of similar metallicity. The chemical composition of Gaia1 does not support an extra-galactic origin for this stellar cluster, that can be considered as a standard Galactic open cluster.

Accepted for publication to A&A Letter

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• Constant light element abundances suggest that the extended P1 in NGC 2808 is not a consequence of CNO-cycle nucleosynthesis
• A new set of chisels for Galactic archaeology: Sc, V and Zn as taggers of accreted globular clusters
• Blanco DECam Bulge Survey (BDBS) III: A new view of the double red clump in the Milky Way bulge through luminosity and color distribution
• Detailed chemical abundance analysis of the thick disk star cluster Gaia 1
• Difference in chemical composition between the bright and faint red clump stars in the Milky Way bulge
• Spectroscopic confirmation of the low-latitude object FSR 1716 as an old globular cluster