Investigation of Rotational Splitting in the Pulsating White Dwarf GD 154

TL;DR

This study observed the pulsating white dwarf GD 154 over a season, detecting signs of rotational splitting through Fourier analysis, confirming regular peak spacings consistent with previous observations, and enhancing understanding of its internal rotation.

Contribution

The paper provides the first detection of rotational triplets in GD 154 using long-term observations and Fourier analysis, confirming the presence of rotational splitting in this star.

Findings

Detected regular peak spacings around 3.7 and 2.6 microHz.

Confirmed the presence of rotational triplets in GD 154.

Results are consistent with previous Whole Earth Telescope data.

Abstract

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.