Enlarged view of the diffusion portrait shown in Fig. 1 limited to a₂ ≤ 7 AU (upper panel). The same diffusion map for a two planet system around a single star is shown as a comparison in the lower panel. The vertical dashed lines mark the locations of mean motion resonances between the two planets. The dynamics in the binary system appears to be more chaotic in particular close to the inner stability border marked by the 3:2 mean motion resonance between the planets and in correspondence to the 5:2 resonance. These effects are due to the gravitational perturbations of the binary companion.