Left panel: B−V vs. τ_c. The black open circles and five-point stars are MS and post-MS stars identified in Fig. 2. Red squares are from a MWO sample (Lehtinen et al. 2020) whose τ_g is also derived from the YaPSI model. We have plotted four reference relationships (dashed lines) indicating the local τ_c (Noyes et al. 1984; Wright et al. 2011) and the global τ_c (Barnes & Kim 2010; Mittag et al. 2018), after calibrating their B−V scale to this study. Right panel: Comparison between the YaPSI τ_g of MS stars and the empirical τ_l along with effective temperature.