Context :

Aims : We re-examine the effects of Compton scattering on the emergent spectra of hot DA white dwarfs in the soft X-ray range .
Earlier studies have implied that sensitive X-ray observations at wavelengths \lambda < 50 Å might be capable of probing the flux deficits predicted by the redistribution of electron-scattered X-ray photons toward longer wavelengths .

Methods : We adopt two independent numerical approaches to the inclusion of Compton scattering in the computation of pure hydrogen atmospheres in hydrostatic equilibrium .
One employs the Kompaneets diffusion approximation formalism , while the other uses the cross-sections and redistribution functions of Guilbert .
Models and emergent spectra are computed for stellar parameters representative of HZ 43 and Sirius B , and for models with an effective temperature T _ { eff } = 100 000 K .

Results : The differences between emergent spectra computed for Compton and Thomson scattering cases are completely negligible in the case of both HZ 43 and Sirius B models , and are also negligible for all practical purposes for models with temperatures as high as T _ { eff } = 100 000 K. Models of the soft X-ray flux from these stars are instead dominated by uncertainties in their fundamental parameters .

Conclusions :