(Top) Action space diamond, the difference between the vertical and radial component of the action, vs the rotational component of the action with the axes normalised by J_tot = |J_ϕ | + J_r + J_ɀ for confined and confined planar stars as defined in section 4.2 and prograde planar (disc-like) stars, as defined in section 5.1. All EMP stars observable by the spectroscopic follow-up program are shown in grey (Bottom) Apocentre and Z_max distribution of these stars are shown in the same colour.