Examples of different radial velocity distributions on the planetary disk and resulting velocity profiles, and the result from the retrieval. The example profiles assume a limb darkening coefficient of ϵ = 1. (a) Tidally locked rotation (according to WASP-189 b’s orbital period), (b) Day-to-night wind of v_day–night = 5 km s⁻¹. (c) Zonal jet with a speed of v_jet = 5 km s⁻¹ and a width of σ_jet = 0.3 R_p. (d) Velocity distributions according to the best-fitting parameters from the retrieval, and the average retrieved line profile calculated from 1000 random samples. The shaded region indicates the 1σ uncertainty interval.