Detection limits versus the noise levels after correction for various sampling (black lines): 1 day (solid line), 8 days (dotted line), and 20 days (dashed line), averaged over the 20 realizations of the noise. The green curves show the detection limit for for the same sampling (same line code). The upper horizontal red line corresponds to the detection limit before correction for the 1 day sampling, and the horizontal yellow line the 1 M_Earth detection limit level.