Perturbation of the binary eccentricity caused by a perturber on a distant, circular orbit. The perturber has a mass of 48   M_J and its orbital period is 13.4 times that of the binary. The three panels show that the perturbation occurs at three different timescales: that of the binary P₂ (0.0595^d) panel a), that of the perturber (0.7975^d) panel b), and a much longer modulation (875^d) panel c).