Single-star evolutionary tracks in the HRD for different stellar masses. Each colour corresponds to a given initial mass, as indicated to the lower left of each line. The coloured open circles indicate where we save single-star models for use in our binary star simulations. We have indicated lines of constant radius using grey dashed lines. Note that we have truncated these tracks to start at the ZAMS, and end at either the first TP or the maximum radius of the star, depending on which occurs first.