Left panel: phase-folded RVs of the four HARPS-N transits of KELT-9b. Different colours refer to different transits. Right panel: mean RVs of the four transits (filled circles), together with single RVs (small dots). The theoretical RV solution (blue line) computed using Keplerian motion and the classical RML effect alone clearly does not match the observations. The vertical dashed lines show the ingress and egress of transit.