(X, Y) projected distribution of TWA-a (red) and TWA-b (blue) members, 9 Myr ago, in the present, in 25 Myr, and 50 Myr from now (from left to right), for the stars in the TWA-6D-HQ sample. The blue open circles in the −9 Myr (left) panel indicate that the stars in TWA-b were not born yet and trace the location of their parent gas. The locus of σ Cen is indicated (black cross). The coordinate system is centered on the Sun’s position in the present and rotates with the Local Standard of Rest (rLSR), so the Galactic Center (GC) is always on the same axis and direction (positive X). The linear fit on the (X, Y) plane has a slope of −0.51 ± 0.15 (present), −0.10 ± 0.07 (in 25 Myr), and 0.58 ± 0.06 (in 50 Myr).