Polar plots of CO, N₂, and HCN abundances in WASP-76 b. The left-hand column shows a model that does not incorporate photochemistry, the right-hand column shows the full model with photochemistry. Photodissociation forms a strong additional destruction mechanism for day-side species. HCN formation on the planetary night side is only initiated when photochemistry is taken into account. All plots display an equatorial slice of the planet. At the evening and morning limbs, radial lines indicate the opening angle that is probed during transit (32°).