Age constraints derived on the basis of two sets of evolutionary models, derived using effective temperature – mass relationships. The curves shows the photocentric orbit size α_C for various ages and fixed effective temperatures, where the solid and dashed curve corresponds to the DUSTY and Saumon & Marley (2008) models, respectively. The shaded regions delineate the uncertainties (dark grey for DUSTY, light grey for Saumon & Marley 2008). The horizontal lines show the measured value of α and its uncertainty. Vertical dotted lines indicate age limits derived from the photocentric orbit.