Relation between masses of components in the synthesized population of binaries with HeS stars. Different symbols denote the descendants of binaries with different initial mass ratios of components, q₀. The symbols are color-coded by the T_eff of HeS stars. The gray scale codes the number of stars per Δ(M_HeS)  ×  Δ(M₂) = 1.0 M_⊙ × 1.0 M_⊙ pixel. Solid and dashed magenta lines show roughly two limiting values of the UV color excess (GALEX/NUV-SDSS/r) computed by Götberg et al. (2018), below which HeS stars may be detected due to their color excess compared to the UV color of the companion (assumed to be a main-sequence star).