Left: CCFs in units of S /N for H₂O in the atmosphere of β Pic b. Thick red line: Actual CCF for the location of the planet. Thick black line: CCF for the location at the opposite side of the star. Thin lines: CCF for injected H₂O, colour coded by different volume mixing ratios as shown in the colour bar. Right: S /N of injected signals as function of VMR. The green shaded area shows at which range of VMRs the molecule would have been marginally detectable.