Companion radius, R, and surface gravity, log(_g), as a function of effective temperature, T_eff. The dotted grey lines indicate isochrones of different ages, the dashed lines illustrate evolutionary tracks, i.e. how a companion of a certain mass evolves over time. The specific masses that the tracks correspond to are indicated by their respective colours. Both the isochrones and the evolutionary tracks are taken from the AMES-Dusty model grid (Chabrier et al. 2000; Allard et al. 2001). The hexagonal bin map in the background shows where a sample of pairs drawn from the mass and K-band magnitude distributions falls when propagated into the parameter planes depicted in the two respective panels using AMES-Dusty. Finally, the values obtained through the atmospheric models applied to the spectral energy distribution of the companion are marked as circles of different colours.