Biennal mean surface temperatures of completely dry atmospheres, for 2 orbital configurations (synchronous and 3:2 orbital resonance) and 4 atmospheric compositions and pressures (6 bars of pure CO₂, 4 bars of pure CO₂, 1 bar of pure CO₂ and 1 bar of N₂ + 376 ppm of CO₂ – Earth-like atmosphere). The solid black line contour corresponds to the 273.15 K isotherm; the dashed blue line contour indicates the regions where the atmospheric CO₂ collapses permanently into CO₂ ice deposits. The 1 bar pure CO₂ (synchronous) simulation is not stable in the long term since CO₂ would collapse at the two cold points.