Vertical profiles of H₂O, CO, and CO₂ derived fromthe time-dependent model under these assumptions: (i) 1.1 × 10¹⁵ gr of CO are brought to the planet via a cometary impact ~630 yr ago (case 3 in Table 4), and (ii) vapour water input is due to the ablation of ice grains (Moses & Poppe 2017) with an integrated rate of 6.0 × 10⁴ cm⁻² s⁻¹. Red solid line: CO, blue solid line: H₂O, dashed green line: CO₂ only produced by chemical processes, and green solid line: carbon dioxide when an integrated ice grain ablation rate of 4.5 × 10⁴ cm⁻² s⁻¹ is considered as well.