Left upper panel: distribution of cerium vs. metallicity for the low-uncertainty sample stars, colour-coded with the eccentricity of their orbits. Left lower panel: Toomre diagram colour-coded with [Ce/Fe]. The circular dashed lines corresponds to V_Tot = 50, 100 and 150 km s⁻¹. Right panels: Energy-angular momentum (E, L_Z) plane colour-coded by density (top panel), and medium cerium abundance (lower panel). The white star indicates the solar neighbourhood (L_Z = L_⊙, ).