Period spacings in gamma Dor stars

Recent space missions such as Kepler have provided us with an opportunity to study these oscillations with unprecedented detail. For many multi-periodic pulsators such as gamma Doradus stars, this led to the detection of dozens to hundreds of oscillation frequencies that could not be found from ground-based observations.

We aim to detect non-uniform period spacings in the Fourier spectra of a sample of gamma Doradus stars observed by Kepler. Such detection is complicated by both the large number of significant frequencies in the space photometry and by overlapping non-equidistant rotationally split multiplets. Guided by theoretical properties of gravity-mode oscillation of gamma Doradus stars, we developed a period-spacing detection method and applied it to Kepler observations of a few stars, after having tested the performance from simulations.