Analysis of Trans-Neptunian and Centaur colours: continuous trend or grouping?

We report the results of the first statistical analysis of colours (B - V, V - R, V - I, and V - J) of the Trans-Neptunian and Centaur populations. Us ing the same statistical techniques applied to define the current asteroid taxonomy, we find a continuous spread of the objects between neutral colour to very red. Pushing further the analysis, the TNOs may be split into four groups. The differences in colour content are interpreted as a consequence of the TNOs evolution (i.e. collisional history, space weathering, ...)