Top: comparison between the bolometric data (histogram) and the best model with three uniform-temperature circular spots plus a modulated power law (red line). Bottom: residuals between the data and the best model. Here, we plot two full rotational cycles, with 32 uniformly distributed rotational phases per cycle. In addition to the overall adequate bolometric χ²/dof = 33.39/27 (18% probability if the model is correct), we see no strong outliers and no obvious patterns in the residuals. As with the phase-channel χ, this is a one-way test, which might detect a strong deviation between the model and the data but cannot guarantee the model’s correctness if it passes the test.