Parameterized modifications to the optimized DALI model described in Appendix A. Right and right-middleplots: gas temperature and CO abundance, respectively. The black dashed box shows the modified region. Left-middle plot: DCO⁺ abundance map calculated with DCO+ CHEMNET with the 30–70 K constant abundance warm component included. Left plot: DCO⁺ radial intensity profiles of the data (solid black with shaded gray 1σ errors) and of the model with the cold component only (C only; dashed blue) and with warm component included (C + W; dashed red). Top: optimized DALI model with no modifications made to the gas temperature or CO profile. Middle: cold disk model. The gas temperature is decreased by 2 K in the black dashed region. Bottom: shadowed and depleted cold disk model. This is an extension of the cold disk model to simulate a secondary colder region beyond the millimeter dust edge. The gas temperature is decreased by 8 K with CO depleted by a factor of five from r = 83−120 AU. The gas temperature is decreased by 2 K for r > 120 AU.