Streamline model of the HC₃N blue-shifted emission for the set of parameters (r₀, θ₀, ϕο) = (5000 au, 41°, −170°) around the (ℜ_z) axis, with υ_r,0 = 0 km s⁻¹ (pink), υ_r,0 = 0.31 km s⁻¹ (blue) and υ_r,0 = 0.78 km s⁻¹ (orange). See Sect. 4.2.2 for more details. Left: Theoretical projected trajectories from the streamline model overlayed on the HC₃N blue-shifted emission and the two brightest peaks of the SO emission of Fig. 7. The contour levels are 7σ to 19σ by 2σ steps where σ = 0.89 mJy beam⁻¹ km s⁻¹. The black contour delimits the mask used to compute the KDE. Right: Theoretical line of sight velocities profiles from the streamline model overlayed on the KDE of the HC₃N blue-shifted emission. The vertical dotted line corresponds to the disk v_LSR = 7.37 km s⁻¹, the horizontal to the 0″ offset.