Mapping non-radial pulsation using surface imaging techniques

We apply stellar surface imaging techniques for studying non-radial pulsations. Stellar surface imaging is based on inversions of time series of variable spectral line proflles without making assumptions on the speciflc shape of the pulsations. The inversion results in an image of the stellar surface in which the sectoral and tesseral modes can in many cases be distinguished, and the pulsational degree l and the azimuthal order jmj can be determined. We apply this method to simulated data for testing the method (Berdyugina et al. 2003a). The tests show that the tesseral modes with l ijmj = 2 (or any even number) can be successfully recovered. Pulsation modes that are antisymmetric with respect to the equator, i.e. when lijmj = 1 (or any odd number), are di‐cult to recover accurately.