Top panels: semi-major axis as a function of time, relative to the orbital period, for models Q2e02 to Q2e08 (solid lines). Notice that since the change in the orbit is very small (between 10⁻⁴ and 10⁻² AU), for better visualisation the order of magnitude of the quantities along the y-axis is given in the top-left corner. Bottom panels: eccentricity as a function of t/P for models Q2e02 to Q2e08 (solid lines). Similar to a, the order of magnitude of the quantities along the y axis is given in the top-left corner. The dashed lines in each panel show the moving average of a and e over the interval [t/P − 0.5, t/P + 0.5], for better appreciation of the long-term trend. We only show the evolution of a and e for the last five orbits of our simulations. The dotted grey lines correspond to the distance between the stars, with the minimum corresponding to periastron and the maximum to apastron.