Variations in WASP-107 line contrast measured with HARPS. Upper panel: contrast as a function of the projected distance to the star center $r=\sqrt{1-{\mu }^2}$ (for a given exposure time the range covered by the planet in r is closer to being constant than in μ). Measurements, derived from the fit to individual exposures (Sect. 4.3.2) in each visit (1 = blue, 2 = red, 3 = green), are binned into the black points. The dotted black line is the best-fit model from the joint RMR fit, to be compared with a constant contrast of 50% (horizontal gray line). Lower panel: average CCF_intr at r = 0.34 (orange, from profiles over r = 0–0.5) and at r = 0.72 (purple, from profiles over r = 0.5–1). The stellar line keeps its Gaussian profile but is markedly deeper toward the limbs.