Context : The surface gravities of cool ( T _ { eff } < 13 , 000 K ) hydrogen-atmosphere DA white dwarfs , determined from spectroscopic analyses , are found to be significantly higher than the canonical value of \log g \sim 8 expected for these stars .
It was recently concluded that a problem with the treatment of convective energy transport within the framework of the mixing-length theory was the most plausible explanation for this high- \log g problem .
We pursue the investigation of this discrepancy by computing model spectra of cool convective white dwarfs from a small sequence ( 11,300 K < T _ { eff } < 12,800 K ) of 3D hydrodynamical model atmospheres , which feature a sophisticated treatment of convection and radiative transfer .
Our approach is to proceed with a differential analysis between 3D and standard 1D models .
We find that the 3D spectra predict significantly lower surface gravities , with corrections of the right amplitude as a function of effective temperature to obtain values of \log g \sim 8 on average .
We conclude that the surface gravity distribution of cool convective DA white dwarfs is much closer to that of hotter radiative objects when using , for the treatment of the convection , 3D models instead of the mixing-length framework .

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