Rotation periods as a function of effective temperature for a group of 66 low-mass MS stars in the Kepler field (the same stars that are represented in Figure 1 with red color, and that serve as references for the theoretical models). Red circles represent observational data. Blue circles represent theoretical data. Specifically, they denote the $\overline{\mathrm{\Gamma }}$ values computed for different regions within the star, as indicated on the right y-axis of each subplot. Also plotted in this figure is a linear regression model fit to each set of data. The shaded area around the regression line represents a 95% confidence interval for the regression estimate.