Radius-temperature diagram of the stars available in Berger et al. (2018) in the range [0.2, 100] R_⊙ and [3000, 7500] K. Radii are from Gaia and temperatures from the Kepler MAST archive. Temperature axis is reverse, that is with higher T_eff toward left. Color-coding represents logarithmic number density. The colored part of the diagram indicates the location of our sample. The red line indicates the limit between subgiant and giant stars according to Berger et al. (2018), such as the RGs lay at the top-right corner. According to Berger et al. (2018), the discontinuity in T_eff near 4000 K is an artifact due to systematic shifts in T_eff scales in the DR25 Kepler Stellar Properties Catalog.