Top row: Dust surface density (color) with superimposed gas (cyan) and dust (white) velocity streamlines. Bottom row: Time evolution of the normalized torques exerted on the embedded moon. The solid black curve shows the net (gas + dust) torque, while the red and green curves correspond to the dust and gas contributions, respectively. The dashed green curve indicates the net gas torque in the corresponding dust-free reference simulation. Simulation corresponds to protomoon with ϵ = 0.025 and T_s = 0.35.