CCFs of H₂O for the two nights of KELT-11 b. For each night, the shown CCF corresponds to the optimised number of SYSREM iterations as detailed in Table 3. The planetary rest frame follows a trail between the dashed white lines. The horizontal dashed lines indicate the contact points (T1, T2, T3, and T4, from bottom to top). Due to the long transit duration of KELT-11 b, the end of the transit was not covered on either of the two nights.