V − U (left) and e-J_Z diagram (right) for our 12 targets. The white dwarf sample (+) of Pauli et al. (2006) serves as reference. The solid ellipses render the 3σ-thin and thick disc contours, while the solid box marks the thick disc region (Region B). Ten of our targets are outside of the regions for the two disc populations in both diagrams, but form two distinct groups. The five stars inside the dashed ellipse are called group 1 (G1), while the stars with negative J_Z are defined as group 2 (G2).