Average neutral sodium light curve constructed using 1.5 Å band width from the core of both Na D|$_{1}$| and Na D|$_{2}$| lines. The white region indicates the transit duration, the blue region is |$\sim \frac{1}{2}$| the Hill sphere, and the green region indicates the out-of-transit observation. The estimated transit duration of the sodium signal from the best-fitting Gaussian (red dashed line) is 40.05 |$\pm$| 3.2 min. The average value of the blue and green data points used as ingress and egress in Fig. 6, respectively.