Global stability of asteroid motion with a) and without b) the mutual interactions of Ceres, Pallas, Vesta, Iris, and Bamberga. The initial conditions are taken on a regular grid of 701 × 51 in (a,e). The color index, obtained through frequency analysis (Laskar 1993), is the measure of the diffusion in mean motion (and thus in semi-major axis through Kepler’s law) over two consecutive time intervals. Blue denotes very regular regions and red highly chaotic ones.