Mass-radius diagram, on logarithmic axes, showing the positions of the ten very-low-mass stars (red, square), binary stars from the literature (black, circular) and comparable literature objects selected to expand the sample (blue, diamonds). The literature objects are detailed in Table 3 and Chen et al. (2014). Several sub-stellar objects are also shown. The Exeter/Lyon (Baraffe et al. 2015, 2003, 1998) 1 Gy (red) and 5 Gy (blue) isochrones are shown, for solar metallicity [Fe/H] = 0 dex (solid line), and sub-solar metallicity, [Fe/H] = −0.5 dex (dashed line). Iso-surface gravity lines are shown for log g₂ = 4.5 dex to log g₂ = 5.5 dex (cgs). Objects are constrained to their surface-gravity line by the log g₂ measurement, derived from the transits and radial velocities without invoking the primary mass.