The impact of photochemistry on the emission spectrum of LTT 1445A b. Two atmospheres are simulated: 1 bar O₂ with 10⁻⁴ bar CO₂ (left panel), and 1 bar O₂ with 10⁻² bar CO₂ (right panel). Solid lines are the results of coupled photochemical-climate simulations, and dotted lines are climate-only models. This sensitivity test demonstrates that photochemically produced O₃ has a relatively small impact on the planet’s emission spectrum when compared to the existing low-precision data.