Colour-magnitude diagram of the Gaia-ESO parent sample (black dot). Spectroscopic binaries are overplotted: SB2 (red disc), SB3 (cyan diamond), and SB4 (magenta plus). ℳ_G is the absolute magnitude in the G band. The blue and green thick lines are respectively a quartic and quadratic fit of the rebinned parent-sample main-sequence and of the rebinned SB2 sequence. The width of the lines materialises the 1 – σ uncertainty on the locus of these two trends only due to the uncertainties on the parallaxes and photometry; the thickness of these lines is therefore not related to the vertical scatter of the datapoints. Left: photometric quantities are not corrected for the extinction. Right: photometric quantities are corrected for the extinction by using A_G and E(G_BP − G_RP) from Gaia DR3.