Pre-shock velocities (upper panel) and post-shock cooling parameters (lower panel) derived from the 3D hydrodynamic simulation. For comparison, curves are shown for one-dimensional static-star model estimates (which include wind acceleration and the radiation fields of both stars). The dashed line in the lower panel corresponds to χ = 3; when χ ≲ 3 gas cools effectively within the post-shock region where emission predominantly originates from.