Lensing light curve of UKIRT11. In the inset of the lower panel, the three empty circles on the source trajectory, labeled t₁, t₂, and t₃ , represent the source positions at the times of consecutive approaches to the caustic cusps. The size of each circle is scaled to the size of the source. The times corresponding to these positions are indicated in the light curve by arrows. The dotted curve in the top panel represents a 1L1S model derived by excluding the data points around the anomaly.