Heavy elements in old very metal-rich stars

The low pericentric distances and eccentric orbits of these solar neighbourhood stars indicate that they might have originated in the inner parts of the Galaxy. Chemical tagging can probe the formation history of stellar populations.

To identify the origin of a sample of 71 very metal-rich dwarf stars, we derive the abundances of the neutron-capture elements Y, Ba, La, and Eu. The abundances of Y, La, Ba, and Eu vs. Fe, O, and Mg as reference elements, as well as their kinematics, suggest that our sample of old metal-rich dwarf stars is clearly distinct from the thin disk. They could be old inner thin-disk stars, as suggested previously, or bulge stars.