Left panel: calculated (curves) versus measured (shaded horizontal region) occultation depths as functions of the heat redistribution efficiency. Different curves with assumed values of A_g are shown. As a sensitivity test, the shaded region associated with each curve corresponds to a variation in metallicity within a range of [M∕H] = 0.2 ± 0.3. Right panel: theoretical spectral energy distribution, at a low and high resolution of the star (blue curve) with the CHEOPS bandpass (black dot-dashed curve) overlaid. The model for WASP-189 b (with A_g = ɛ = 0) is overlaid in orange, with the corresponding temperature–pressure profile shown in the inset. For comparison, a blackbody curve with a temperature of 3345 K is also overlaid (orange dashed line).