[C/N] ratios as a function of T_eff (top). The dashed line at [C/N] = −0.6 dex separates the mixed and unmixed stars. Middle panel: [N/Mg] ratios as a function of [Mg/H]. The horizontal dashed line at [N/Mg] = ~0.43 dex indicates the mean value for the ratio [N/Mg]. Lower panel: log(C/N) as a function of [Fe/H]. Symbols are the same as in Fig. 7. A representative error bar is plotted in the upper-right corner of the panels.