Dependence between donor mass (M_⊙), orbital period (days), and eccentricity of XRBs for all three models. The eccentricity is color coded and the open symbols represent the population of XRBs described in Sects. 6.2.2 and 6.2.3: HMXBs are plotted as open squares, IMXBs as open diamonds, and LMXBs as open circles. The crosses are XRBs that become merging DCOs generated in ten runs for each model, as is described in Sect. 7.3. It means that the DCO progenitors are ten times over-represented with respect to other XRBs in the plots to show which part of the parameters space they occupy.