CO₂ flux versus stellar luminosity for three different features in the spectrum. All fluxes have been normalized to the flux of the 1 L_⊙ model. Both the flux in the 14.7 to 15 μm region, which corresponds to the v₂Q-branch, and the flux from the 01¹0Q(6) line have a nearly linear dependence on the stellar luminosity. The dependence of the 00⁰1R(7) line at 4.3 μm on source luminosity is more complex.