Extended Data Fig. 2: Accretion shock modelling.

We show the best-fitting models (red solid line) to HST NUV–NIR spectra (black solid line). The total model consists of a non-accreting template star (blue dotted line) and three components with energy fluxes of 1 × 10¹⁰ erg s⁻¹ cm⁻² (green dashed line), 1 × 10¹¹ erg s⁻¹ cm⁻² (grey dashed line) and 1 × 10¹² erg s⁻¹ cm⁻² (red dashed line). Best-fitting model parameters are listed in Extended Data Table 2. λ and F_λ are the wavelength and flux density, respectively.