Light curves for low mass-transfer rates. For the black and red curves, Ṁ_tr = 10¹⁴ g s^-1, the orbital parameters and the viscosity being identical to those of Fig. 2. The black line shows the case of a truncated disc with an inner disc radius given by Eq. (7). The red curve corresponds to a fixed inner radius of 2 × 10⁸ cm. The green and blue curves correspond to Ṁ_tr = 10¹³ g s^-1, the inner radius being equal to 0.15 times the value given by Eq. (7). The viscosity parameters are α_h = 0.2. α_c = 0.01 (green curve) and α_h = 0.1. α_c = 0.01 (blue curve).