Spectral type versus effective temperature for all stars used in this analysis. The stars have been binned in three different age bins, as indicated in each panel. The grey shaded area represents the range of values within each spectral bin; the black marker is the mean value. Also plotted are the results of Pecaut & Mamajek (2013) – green line, Luhman et al. (2003) – dotted blue line, and Bayo et al. (2011) – solid red line for comparison.