Orbital maps of the Y-asymmetric orbits with |Z|< 0.75 kpc and −1 < [Fe/H](dex) < 0.5. Left two plots: density maps built by superposing of model (left) and APOGEE stellar (right) Y-asymmetric orbits. The model density map has been normalised to a similar scale as the APOGEE density map using the factor n. Right two plots: mean [Fe/H] (left) and age (right) maps built from the Y-asymmetric APOGEE stellar orbits. The red contours in the APOGEE maps show specific density levels to guide the eye. For other plot details see Fig. 2.