Colour-colour diagram used to identify sources that are likely affected by extinction. Sources that offset from the main population by more than 5× the mean error in the used colours, i.e. 0.017 in (G − G_BP), are considered to be reddened. The main population is fit with a second-degree polynomial (dashed line). The dashed line is offset by 0.017 in (G − G_BP) to indicate which sources are reddened, i.e. those above the line. The members identified in the full 6D sample are shown with green markers, those without radial velocities are blue.