Dependence of the radius of the τ = 1 radio photosphere as a function of wavelength for the primary (P), the secondary (S) and the tertiary (T) components. The vertical lines are located at 3.6, 6, 13, and 20 cm corresponding to the wavelengths investigated by Benaglia et al. (2006). We stress that the separation between P and S is estimated at asini = 28.9   R_⊙ whilst the separation between (P+S) and T is between 3500 and 9100 R_⊙.