Modeled reflection (left column) and emission (right column) spectra for planetary “edge cases” around the Sun. Each row represents a different pCO₂ value of 5, 7.5, and 10 bar, respectively. Blue spectral lines indicate the highest insolation for each pCO₂ considered that does not reach equilibrium. Red spectral lines denote the lowest insolation that reaches equilibrium and is considered to be a habitable planet. H₂O features are noted with black lines. All unlabeled features correspond to CO₂. Temperature values that correspond to these insolation values can be found in Table 2.