Pure CO₂ case. Upper panels: Observables (right: phase curve at 15 µm, left: eclipse depth). The dotted lines represent non-stable atmospheres; these are snapshots of the atmosphere during its collapse. Lower panels: Physical quantities. Temperature profiles and temperature map for the 10 Pa case (compatible with the observations, but not stable). In the lower right panel, the red contour shows the CO₂ ice caps. The red dot is the substellar point. In the lower left panel, the red line corresponds to the CO₂ condensation curve.