Artifact transmission spectrum with the center-to-limb variation (CLV) and Rossiter–McLaughlin (RM) effects. In each panel, the top sub-panel shows the phase-resolved CLV+RM combined model in the stellar-rest frame, where the first and fourth contacts of the transit are marked by horizontal lines and the planet orbital motion is traced by the dashed line. Bottom sub-panel: in-transit combined (between the first and fourth contacts, dotted line)and fully in-transit combined (between the second and third contacts, solid line) “transmission spectra” in the planet-rest frame. The CLV-only, RM-only, and CLV+RM combined models are shown in green, blue, and red colors, respectively.Panels (a–c): experiments with different impact parameters, where (b) refers to the real case of WASP-52b. Panels (d–f): adopt the same impact parameters as WASP-52b, but employing a different v sin i in (d) and (e), or a different λ in (e) and (f).