Two-dimensional heat maps illustrating the preferred parameter space (colour-coded by the change in BIC) for accurately detecting stellar DR as a function of projected obliquity and stellar inclination for three different impact parameters (b = 0.1,0.4, and 0.7 from left to right). Accurate detections are those for which the recovered α agrees with the injected value within 0.05. The behaviour is similar to Fig. 3, where accuracy is ignored, but the cold spots are even larger; regions that change colour between these two figures should be taken with caution in empirical analyses. These results have been obtained with α = 0.2, and the parameters that we held constant in the three figures are listed in Table 1.