HR diagram color-coded by ν_max+Gaia mass and binned by metallicity. Luminosity was computed from Gaia radii. MIST evolutionary tracks for stars with masses between 0.8 M_⊙ and 1.6 M_⊙ and metallicities equal to the central metallicity of each bin are shown for reference. The sample spans an interesting range in mass and age as well as metallicity so that the FDU can be studied (the clump is visible in the MIST tracks as kinks above the locus of the sample); see Fig. 8.