Expected (S/N) for different planet masses as a function of distance. The lines show the cases for 13 Jupiter masses, 1 Jupiter mass, and 1 Neptune mass; with circular orbits at 1, 3, and 4 au (it is only possible to observe a 4 au orbit if the mission length is ~ 10 yr; see Sect. 8). A 1 M_⊙ star is assumed for the solid lines, while a 0.5 M_⊙ star is assumed for the dashed lines.