Decomposition of the Hα emission-line profile in the Haro 11C spectrum. Two Gaussian components (blue dotted lines) are likely related to nebular emission, a P Cyg profile (green dotted line) is a spectral feature of an LBV star. The residual is shown by the black dotted line. For a better view this is shifted below the zero value. Observational data are shown by the black solid line and the modelled profile, which includes all components, is displayed by the red dashed line.