An example of the continuum modeling procedure applied to prepare the extracted JWST/MIRI spectra for retrieval analysis. The data points are the irradiance spectrum in subband 3B obtained from Observation 2 using a 2″–3″ annular aperture. The orange points denote the wavelengths that contain CO₂ fluorescence emission, here masked prior to continuum modeling. The blue curve is the cubic spline fit to the continuum wavelengths, with the smoothing threshold set to 2.5n, where n is the number of continuum data points. See the text for more details.