Top panel: the fit of the X-ray burst data for 4U 1724–307 by the theoretical models for the NS atmosphere. The circles indicate the observed dependence of K^−1/4 versus F for the long burst (S11) and the solid curve corresponds to the best-fit theoretical model for a pure hydrogen atmosphere and log g = 14.0. Vertical dotted and dashed lines show the best-fit value for F_Edd for the old and new models. Bottom panel: constraints on mass and radius of the NS in 4U 1724–307. The new (solid) and the old (dashed) curves corresponding to T_Edd,∞ are shown. The dash-dotted curve corresponds to the new best-fit parameter A for the distance to the source of 5.3 kpc.