Mass growth in polytropes of indices N = 1 (red curves) and N = 3 (blue curves) as a function of the normalised rotation rate in the case of solid rotation. The upper and lower thin curves represent the equatorial and polar radii in both polytropes, respectively, and the thicker curves indicate their mass. All quantities are expressed in units of the non-rotating models’ parameters, and the percentages on the right side give the relative mass increase at Ω = 0.9Ω_K with , the Keplerian rotation rate. The colour maps adjoining the curves depict the mass distribution in both models after deformation at Ω = 0.9Ω_K.