﹩{R}_{{\rm{HK}}}^{+}﹩ and ﹩{R}_{8542}^{+}﹩ as functions of T_eff, ﹩\mathrm{log}g﹩, and [Fe/H] for the LAMOST sample, derived using the A1 templates with ﹩{V}_{{\rm{mic}}}={V}_{{\rm{mic}}}^{{\rm{t}}}﹩. The upper panels show ﹩{R}_{{\rm{HK}}}^{+}﹩, and the lower panels show ﹩{R}_{8542}^{+}﹩. The red star marks the Sun, for which ﹩{R}_{{\rm{HK}}}^{+}=0.0252﹩ and ﹩{R}_{8542}^{+}=-0.0018﹩. In the T_eff panels, the red curve denotes the 5th percentile relation. High-density regions are shown in yellow, and the median lines are plotted in red. The black horizontal dashed line indicates R⁺ = 0.