Position in the CMD, corrected for interstellar extinction, of stars in the VHA (upper left panel), HA (upper right panel) and LA (lower panel) branches. Input APs are from GSP-Phot. The density plot of all sources for which the activity index has been derived is shown in grey on the background. The position of subsamples of ∼2000 stars per branch are shown in each panel, colour coded according to . See text for details.