Illustration of the ingress–egress asymmetry produced by an oblate planet. Top: transit geometry. The planet’s projected shape is elliptical, with projected flattening f_⊥. The intersections of the ellipse with the stellar limb are nearly straight lines but with different lengths L, leading to different rates of ingress and egress. Bottom: example light curve (red) with exaggerated projected oblateness (f_⊥ = 0.8). The resulting asymmetry between ingress and egress (green) underlies the geometric factor F used in our detectability metric (Appendix A).