¹²CO emission for HD 121617. Left: velocity integrated intensity map created by shifting the spectral emission and integrating along the velocity axis for all channels with emission above 4σ. Middle: peak intensity map generated using the quadratic method with bettermoments. Right: linewidth FWHM map produced by dividing the velocity integrated intensity map by the peak intensity map and converting it to FWHM, assuming a Gaussian line profile shape. The beam size is shown in the lower-left corner of each panel. The horizontal white bar indicates 50 au. The corresponding maps for ¹³CO can be found in Appendix B.