Kiel-diagram of the 173 stars from C6–19 with detected oscillations analysed in this study, in addition to the 33 C1–3 stars of Chaplin et al. (2015) and Lund et al. (2016b). Red circular markers indicate stars with log 𝑔 and T_eff values from our spectroscopic analysis (Sect. 4.1.1), while blue circles indicate stars where these were only available from the IRFM (Sect. 4.1.2). The green squares indicate the SPC values for the C1–3 stars (Lund et al. 2016b). The 625 solar-like oscillators from Kepler SC data are shown with smaller gray background markers, using log 𝑔 and T_eff from Mathur et al. (2022). The yellow markers to the upper right show the high-log 𝑔 part of the Yu et al. (2018) sample of Kepler giants. The full red line marks a ν_max equal to the Kepler LC Nyquist frequency of ~283 µHz. Evolutionary tracks were calculated using GARSTEC (Weiss & Schlattl 2008) with [Fe/H] = 0.