Dayside thermal flux from WASP-189 b as a function of the Bond albedo A_B and the heat redistribution efficiency ε. The flux F_day is normalised by the stellar flux F_⋆. Both fluxes are computed as seen through CHEOPS passband. White dotted lines show constant flux ratios across the (A_B, ε) plane. If the measured eclipse depth contains a thermal emission component with an amplitude 40 ppm, the Bond albedo may be as large as ~0.29 and as small as zero, and the corresponding heat redistribution efficiency would be zero and ~ 0.45, respectively.