Number of transits needed to reach a 3σ detection using only the O₂ A-band (top panel), B band (middle panel), and NIR band (bottom panel), assuming host stars of spectral types M1V, M4V, and M9V. The solid lines show results when we only include white noise in the simulations. The dashed lines show results when we include red noise. The simulations using a M9V host star produce very large numbers of required transits in the case of the A and B bands, and are therefore not included in those panels.