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

## TL;DR

This study analyzed the chemical composition of Gaia1's stars and found it to be consistent with typical Galactic open clusters, challenging the idea of an extragalactic origin.

## Contribution

It provides detailed chemical abundance measurements for Gaia1, demonstrating its similarity to Galactic open clusters and refuting previous extragalactic origin hypotheses.

## Key findings

- Gaia1 has solar iron abundance ([Fe/H]=+0.00).
- Chemical ratios are similar to Galactic thin disk stars.
- No evidence of intrinsic abundance spreads in Gaia1.

## 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.