Hertzsprung-Russell diagram: evolutionary tracks of Clés models for the secondary star of M_init = 7.5 M_⊙ (water green), 7.7 M_⊙ (dark blue), and 8.0 M_⊙ (orange), and D_T = 0 cm² s⁻¹ (solid line), 2 × 10⁵ cm² s⁻¹ (dashed line), and 5 × 10⁵ cm² s⁻¹ (dotted-dashed line). All models have α_ov = 0.30 and ξ = 0.1. The filled 5-branch stars over-plotted on the tracks correspond to the models for which the age is equal to the age of the best-fit models of the primary star (i.e. about 9 Myr). The observational value is represented by the red point, and its error bars are represented by the dark red parallelogram.