  We studied a sample of high proper motion, old and metal-rich dwarf stars,
selected from the NLTT catalogue. 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 spectroscopic analysis is based on optical
high-resolution echelle spectra obtained with the FEROS spectrograph at the ESO
1.52-m Telescope at La Silla, Chile. The abundances of Y, Ba, La, and Eu were
derived through LTE analysis, employing the MARCS model atmospheres. The
abundances of Y, Ba, La, and Eu vs. Fe and Mg as the reference elements
indicate similarities between our sample of old metal-rich dwarf stars and the
thin disk. On the other hand, the abundance ratios using O as the reference
element, as well as their kinematics, suggest that our sample is clearly
distinct from the thin-disk stars. They could be old inner thin-disk stars, as
suggested previously, or bulge stars. In either cases they would have migrated
from the inner parts of the Galaxy to the solar neighbourhood.
