Spectral model fit of SSN 9. Top panel: SED fit of the model (red) to the flux calibrated observations of HST-STIS (blue). The blue squares with numbers mark the measure photometric data from Sabbi et al. (2007) which are used as additional constraints for the SED fit. Middle panel: Normalised HST-STIS spectrum (blue) overplotted by our synthetic spectrum (red). Lower panels: Same as the panel above, but now zoomed on the N v, O v and C iv UV resonance lines.