Binarity of different stellar groups, based on their position in the CMD. MS stars are marked in orange, stars in the Be-star region in dark green, stars around the cluster TO in red, and blue stragglers in blue. Additional HST sources for which no spectra were extracted are marked with gray dots, and stars without RV measurements are indicated with open circles. Colored filled circles indicate that the star is single, colored diamonds indicate that the star is classified as a binary based on RV variability, and colored triangles indicate SB2s. The individual systems of interest discussed in Sect. 5.3 are labeled.