Top-left: integrated intensity map of the DCO⁺ J = 3 − 2 line from 5.4–8.8 km s⁻¹ after applying a Keplerian mask to the image cube. The synthesized beam and AU scale are shown in the lower corners. Top-right: DCO⁺ J = 3 − 2 integrated intensity map overlaid with white marking the model inner dust cavity, the inner dust ring (R₁ , hatched), the dust gap, and the outer dust ring (R₂, hatched). The synthesized beam and AU scale are shown in the lower corners. Bottom-left: velocity-weighted coordinate map of the DCO⁺ J = 3 − 2 line, clipped at 3.5σ. Solid black contours show the 233 GHz/1.3 mm emission at 7.0 × 10⁻⁵ Jy beam⁻¹ (1σ) × [5, 50, 200]. The synthesized beam and AU scale are shown in the lower corners. Bottom-right: disk-integrated spectrum of the DCO⁺ J = 3 − 2 line before Keplerian masking, Hanning smoothed to 0.17 km s⁻¹ channels. The horizontal dashed black line indicates the continuum-subtracted spectral baseline. The vertical red line shows the systemic velocity at 6.9 km s⁻¹ .