Detection limits vs. target number for ΔT_spot1 (upper panel) and ΔT_spot2 (lower panel), for different definitions: SN_peak > 6 (black), theoretical fp of 1 % (red, with uncertainty on the fp level, see text). The brown symbols are for blind test with a fap threshold of 1 % made with a random selection between ΔT_spot1 and ΔT_spot2 on both plots. The green line is the detection limit obtained in Theia Collaboration (2017). Circles are for a detection rate threshold of 50 %, and squares for a detection rate threshold of 95 %. Open circles correspond to stars outside the B-V range of our simulations. Downward arrows mean that the detection limits are upper limits (quiet stars), while upward arrows correspond to lower limits (quiet stars). Detection limits of 10 M_Earth are arbitrary (saturation of the detection rate curves, see Fig. D.1).