Surface imaging of stellar non-radial pulsations

We investigate capability of the stellar surface imaging technique for studying stellar non-radial pulsations on the basis of inversions of time series of variable line profiles without making assumptions on the specific shape of the pulsations. The inversion results in an image of the stellar surface in which sectoral and tesseral modes can be distinguished in many cases, and the pulsational degree $\ell$ and the azimuthal order $|m|$ can be determined. We find that sectoral and tesseral modes with $\ell-|m|=2$ (or any even number) can be successfully restored under various conditions (different inclinations of the rotational axis, surface temperature or velocity fluctuations due to pulsations). Tesseral modes with $\ell-|m|=1$ (or any odd number) do not show significant line profile variations at higher inclinations of the rotational axis, and, thus, no information can be recovered from line profiles. At lower inclinations, only the azimuthal order $|m|$ of such modes can be recovered. We conclude that stellar surface imaging is a useful technique for pulsation-mode identification