Stellar radius–effective temperature diagram highlighting seismic detections from Kepler and TESS photometry (blue circles; Mathur et al. 2017; Hatt et al. 2023), and radial-velocity campaigns (red diamonds; see e.g., Arentoft et al. 2008; Kjeldsen et al. 2008, and references therein). The stellar background sample (grey dots) is taken from the TESS Input Catalog (TIC; Stassun et al. 2019). The Sun is represented by its usual symbol. Approximate spectral type ranges (F, G, and K) are delimited by the vertical dashed lines. ϵ Indi (K5 V) is the coolest seismic dwarf observed to date (its interferometric radius and effective temperature were used to place it in the diagram; Rains et al. 2020).