Evolutionary properties of our model d2ns0, neglecting a 2 M_⊙ NS companion and stellar winds. Top panel: surface helium mass fraction of the donor star as function of time during the mass-transfer phase. Bottom panel: evolution of the mass-transfer rate for the same model (left Y-axis). The right axis indicates the X-ray luminosity corresponding to the mass-transfer rate (not Eddington limited) assuming an accretion efficiency of η = 0.15. The dashed line gives the Eddington accretion limit for the NS that is applied in this calculation. Despite the high initial mass ratio of 16.8, the model settles into a stable mass transfer for about 0.25 Myr, with a mass-transfer rate of about the rate of the mass transfer on a nuclear timescale.