Spectrum of HR 10 (black) and the spectral fit (red) computed for the composite model for the stellar parameters given in Table 7. The inset shows a blow-up of the Ca II K profile and the fit. The main narrow features that are not reproduced by the synthetic model – which only accounts for the photospheric spectrum – are the Ti II lines at 375.93 and 376.13 nm, and the Ca II HK lines at 393.37 and 396.85 nm (see Sect. 5).