Hertzprung-Russel diagram of class III sources (left) and class II sources (right), with evolutionary tracks by Siess et al. (2000). The isochrones are for ages of 1, 2, 3, 5, 10, and 20 Myr. Positions of heavily spotted sources with T_ff and L_* based on the 2 T_eff fit are shown as red points, and those obtained assuming a single temperature based on many optical spectral features are shown as blue points. Positions of sources without evidence of spots are shown as black points. The average errors are drawn in the bottom left of each panel.