Evolution of radius, effective temperature, and surface gravity of our models. Observed hypervelocity stars are plotted here for the radius. While the radii of D6-1 and D6-3 are similar to those of D6-2, their age estimate is less certain and spans a bigger region. Due to the association of D6-2 with the supernova remnant (SNR) G70.0–21.5, the purple box is the truncated age estimate for D6-2. The grey band is the mid-plane crossing time for D6-1 and D6-3 taken from Bhat et al. (2025), which assumed they were ejected from the disc and is therefore less wide than the red bands.