Differentiating between blue horizontal-branch stars and blue stragglers. Upper panel: Gaia EDR3 objects that satisfy the modified (Lindegren et al. 2018) and the final CMD criteria (grey dots) with those with the stringent halo criteria and the crowded region criterion applied (blue circles); SDSS SEGUE objects plotting in the blue horizontal-branch region (yellow squares); and SDSS SEGUE objects plotting in the blue straggler region (magenta triangles) in TEFF-LOGG space. Lower panel: SDSS SEGUE TEFF × LOGG plot with blue horizontal-branch (yellow square) and blue straggler stars (magenta triangles).