Colour–magnitude diagram of a simulated cluster brown dwarf population from Saumon & Marley (2008). Each sequence corresponds to a different age as given in the legend. Superimposed we show the positions of several planet candidates and CVSO 30 c. Its unusual blue colour can most likely be attributed to its youth; it is about 2.4 Myr old. The younger the objects, the brighter they are because of not-yet-occurred contraction. Hence they reach the L- and T-dwarf regime at higher brightnesses. If this extrapolation is correct, CVSO 30 c is at the L-T transition, which is roughly consistent with its low effective temperature results. See the discussion and Table A.2 and Fig. A.5 for details.