Transit signal strength in the presence of red noise versus r′ magnitude for the detected and binaries candidates in the previous IRa01, SRc01, LRc01 CoRoT runs (asterisks), LRa01 run (filled circles), and the first seven CoRoT-planets (open circles). D is the transit depth, N is the number of data points in a lightcurve, P is the transit period, and δ = 512 s is the sampling interval. The horizontal dashed lines represent (from top to bottom) the expected signal produced by a Jupiter-size planet with a three-day orbit period, a Neptune-size planet with a three-day orbit period, and a two-Earth radii planet with a one-day orbit period around a solar-like star, respectively. The solid line represents the photon noise.