Ratios of ¹²C/¹³C and C/N of the investigated stars compared with theoretical models. The solid green line represents the ¹²C/¹³C and C/N ratios predicted by the model for stars at the first dredge-up (1 DUP) and the dashed green line represents the minimal values in the model with thermohaline-induced extra mixing (TH), both taken from Lagarde et al. (2017). The solid black line represents the ¹²C/¹³C and C/N ratios predicted by the model for stars at the first dredge-up (1 DUP) and the dashed black line represents the minimal values in the model with thermohaline- and rotation-induced extra mixing (TH+ROT), both taken from Charbonnel et al. (2017). Symbols are the same as in Fig. 3.