Color–magnitude diagram as in Fig. 1, but for the type of variability. The variability types labeled are constant stars (gray dots), low-amplitude variables (green dots), irregular variables (red circles), eclipsing binaries (blue circles), Cepheids (black triangles), long-periodic stars (P > 3 days; purple squares), and candidate rotating variables (yellow pentagons), as defined in Sect. 4. Short-periodic stars do not appear in this diagram for clarity.