Representation of the FLI (3) computed a grid of 500 × 500 initial conditions regularly spaced on (ẋ,ż) (the axes in the picture represent (ẋ₀−ẋ_∗,ż₀−ż_∗); the other initial conditions are x₀ = x_∗,y₀ = y_∗,z₀ = z_∗,ẏ₀ = ẏ_∗), computed for |T| = 300 yrs (top panels) and |T| = 500 yrs (bottom panels); the left panels are a zoom-in of the right ones. The FLI is reported using a colour scale, such that the highest FLI values are shown in yellow. In this way, the yellow curves in the picture correspond to the ridges of the FLI indicator, and pinpoint the set of initial conditions whose orbits have had past close encounters with Jupiter, in addition to the deep close encounter of 1959.