Transit light curve measured in the  − 62 to  − 19  km s^-1 spectral domain. The out-of-transit reference corresponds to the measurements in the orbits #2 (before transit) and #5 (after transit). Upper panel: raw observations. Lower panel: the limb-darkening and all trend correction that are included along with the final global fit (red solid line). All subexposures (black dots for transit #1, blue dots for transit #2 and green dots for transit #3) are shown. The evaluated AD that corresponds to the spectral domain is equal to 6.2    ±    2.9%. Note how flattened the limb-darkening looks: the reason being that the larger Mg i absorption gives a significantly larger planetary radius, which acts to smooth out the limb-darkening profile.