Panel A: L band image reconstruction for the 2021 MATISSE AT observations, which contain the large-medium-small arrays observed within 11 days, at λ = 3.6 ± 0.2 μm using the SPARCO/MIRA software. The central star with T = 7250 K, modelled as a point source centred on (0,0), is not shown. We over-plot ellipses with semi-major axes of the half-light radius l_a, taken from the best parametric fits of Table 3. Panel B: approximate dirty beam of the combined observations at λ = 3.6 μm, together with a small inset of the uv points.