Detectability conditions for Proxima Cen b with the extended VLTI configuration. Left panel show the simulated orbits (black lines) assuming A_𝑔 = 0.3, as well as the mean orbital realisation (as shown in Figs. 4–6) in yellow. Coloured lines show the detectability limits of the interferometer at each spectral band with the VLTI (solid lines) and the extended VLIT (Fig. 8, dotted lines) configurations. In this case, we show the detectability limits for a S/N = 3 in 30 h of integration time, instead of 3 h. The histograms on the right panel show the range of α_obs at each band.