Example MESA track for a binary with a 1.2 M_⊙ donor star, a 0.85 M_⊙ companion, an initial period P_i = 350 days and a metallicity [Fe/H] = −0.15, which produces a hot composite sdB binary. Top panel: track for the donor star in the HR diagram. The mass loss phase is marked in red; the thin red line shows the phase when Ṁ > 10⁻⁹ M_⊙ yr⁻¹, thick red line corresponds to Ṁ > 10⁻⁶ M_⊙ yr⁻¹ and the moment of maximum mass loss is marked with a horizontal red marker. The first He flash is marked with a blue diamond and the core He burning phase is shown in a thick blue line. The phase between the He flash and the core He burning is very short compared to the core He burning phase. Bottom panel: orbital period and mass loss rate during the mass loss phase. The same markings are used as in the HR diagram: the thin black line shows the phase with Ṁ > 10⁻⁹ M_⊙ yr⁻¹, thick black line corresponds to Ṁ > 10⁻⁶ M_⊙ yr⁻¹ and maximum mass loss is marked with a vertical black marker.