Temperature-absolute magnitude diagram of stars in Cygnus OB2 selected by our criteria, assuming for the absolute magnitude a distance modulus DM = 10.8. Isochrones (dotted lines) and evolutionary tracks of stars of various masses (dashed lines) from Lejeune & Schaerer (2001) are plotted. Filled circles are stars of luminosities IV and V, open squares are giant stars of luminosity classes II and III, and open triangles and stars of luminosity class I. Typical uncertainties in both absolute magnitude and temperature as described in the text are represented in the lower right.