NaCo-averaged spectrum (black) of HD 100546 at 0.4′′ or 40 au from the star. The Gaussian decomposition is shown by the red curve, and the hydrogen recombination lines are plotted in grey. Individual contributor spectral signatures are identified at 3.3 μm (black), 3.4 μm (blue), 3.43 μm (green), 3.46 μm (magenta), 3.52 μm (cyan), and 3.56 μm (red). The spectrum is normalised to the continuum at 3.2 μm.