Zoom-in near a caustic with a rogue planet acting as a perturber near the larger microlens. This plot shows a small portion of the critical curve for the same trajectory and microlens as in Fig. 4 but where a small perturber with mass equal to one Jupiter mass intersects the trajectory of the counterimages near the right peak at ≈0.1 microarcsec in Fig. 4. For this plot, the background star is also smaller with radius R = 5 R_⊙. The red dotted lines shows the result obtained with the ray shooting method that does not resolve the small mass perturber.