Analysis of the He I and H I radial profiles as a function of distance to the IF (0.228 pc or 113.4″ from θ¹ Ori C) along a cut crossing the NIRSpec mosaic (see Fig. 1). As the cut is not perpendicular to the IF and distances are given along the cut, a correction factor of cos(19.58°)=0.942 needs to be applied to obtain a perpendicular distance from the IF. Top two panels: observed normalised line intensities of selected transitions. Normalisation factors are listed between brackets. No extinction correction is applied. Units are in erg cm⁻² s⁻¹ sr⁻¹. Third panel: the [He⁺]/[H⁺] abundance. The normalised Br γ radial profile is shown for reference. Normalisation factors are listed between brackets. Bottom panel: the He I 2.058/1.70 radial profile. The dash-dot-dot-dot vertical lines indicate the position of the IF, DF 1, DF 2, and DF 3, respectively, from left to right. The dashed vertical lines indicated the location of the proplyds 203–504 (left) and 203–506 (right).