Isochrones from the BHAC (Baraffe et al. 2015) evolutionary models plotted as 2MASS K-band magnitudes as a function of effective temperature. The isochrones span ages 10, 20, 30, 50, 120, and 400 Myr (from top to bottom). Mass tracks at 0.06, 0.08, 0.1, 0.2, 0.3, 0.4, and 0.5 M_⊙ are displayed going across the isochrones. The binary pairs are included in the figure as coloured circles where the absolute magnitude is calculated from the resolved K′-band magnitudes in Table 7 with either Gaia DR2 parallaxes or statistical distances from Malo et al. (2013). Top panel: effective temperatures (see Table 3) derived from the H₂O–K2 indices; Bottom panel: effective temperature estimated from the K-band continuum fitted to theoretical models. Effective temperatures are listed in Table 3. The bottom panel indicates younger ages, and that the uncertainty for the effective temperature derived from the H₂O–K2 index is underestimated. The J1036 system is depicted by diamonds in the plots, and is the only binary pair for which a dynamical mass estimate exists, estimated to be 0.24 ± 0.07 M_⊙ for each individual component (Calissendorff et al. 2017).