Normalized light curve of red wing (region IV) fluxes during transit of GJ 436 b. The baseline flux used for normalization was computed in the same way as in Fig. 10. Visits A, B, and D display fluxes similar to the baseline value, while Visit C displays a decrease in flux by ~30% in relation to the baseline. The excess absorption in Visit C is likely physical and traces possible inflow of material to the host star.