Temperature as a function of radius within the 70% emitting region of the ¹²CO₂ and ¹³CO₂ ν₂ = 1–0 Q(20) lines (solid green and purple lines). The shaded regions represent the minimum and maximum temperature within the emitting region. The green and purple crosses represent the retrieved T and R_eq for ¹²CO₂ and ¹³CO₂. The left panel depicts the model using the chemical network, and the right panel depicts the model with parameterized abundances.