Relative and absolute density differences between RUBIS and ESTER. Left panel: relative density differences between the models computed with RUBIS and ESTER at given pressure values. The latter are placed according to the position in which these pressure values are met in the RUBIS deformation. The zoomed-in frame helps to reveal the differences in the most superficial layers at the equator. Right panel: same as the left panel, but for the absolute differences in density (expressed this time in units of .