HRD showing the progenitors of TŻO candidates (light blue) and star + NS systems (dark blue) at Solar metallicity (Z = 0.0142). These progenitors are shown at the onset of RLOF leading to a CE event. Two representative single star tracks (Hurley et al. 2000) for 5–20 M_⊙ are shown as solid lines (gray). ZAMS and the terminal-age main sequence (TAMS) are shown as dotted lines (black). The Humphreys-Davidson limit (Humphreys & Davidson 1994) is shown as a dotted line (gray). Above and to the right: Histograms showing the rate density of TŻO and star + NS progenitors in their respective colors. The outline (pink) indicates the subset of systems with a rejuvenated companion. The y-axes of the histograms are scaled by the number of observable SNe in the synthetic population (see Sect. 2.1.2 for more details).