Investigation of Rotational Splitting in the Pulsating White Dwarf GD 154

We observed the ZZ Ceti star GD 154 over a whole season at the mountain station of Konkoly Observatory. Our long time base allowed to detect the sign of rotational triplets around the independent modes. To check whether these can be real detections we made a test on our data set. We searched for characteristic spacing values performing Fourier analysis of numerous peaks determined around five frequencies in the main pulsation region. The analysis revealed regular peak spacings with separations around 3.7 and 2.6 microHz. These values are in accordance with the ones determined by consecutive prewhitening of Whole Earth Telescope observations.