Spectral constraints on the temperature and surface gravity of the Be companion star. The panels show a comparison between the disentangled Be star spectrum (black) with models of different T_eff – logg combinations (see the legend for the respective T_eff and logg values). The blue dashed line represents our fiducial model. The shape of the Balmer line wings favours a surface gravity of logg of 3.5–4.0, as would be expected for a star that is slightly inflated due to recent mass transfer.