envelope. This study was further expanded upon by @Miglio2008a. The authors found characteristic dips to be present in the period spacing series when the influence of a chemical gradient is included in the analysis. The periodicity of the deviations is related to the location of the chemical gradient, while the amplitude of the dips was found to be indicative of the steepness of the gradient. @Bouabid2013 further improved upon the study by including the effects of both diffusive mixing and rotation, which they introduced using the traditional approximation. The authors concluded that the mixing processes partially wash out the chemical gradients inside the star, resulting in a reduced amplitude for the dips in the spacing pattern. Stellar rotation introduces a shift in the pulsation frequencies, leading to a slope in the period spacing pattern. Zonal and prograde modes, as seen by an observer in an inertial frame of reference, were found to have a downward slope, while the pattern for the retrograde [high order]{} modes has an upward slope.

Over the past decade the observational study of pulsating stars has benefitted tremendously from several space-based photometric missions, such as MOST [@Walker2003], CoRoT [@Auvergne2009] and *Kepler* [@Koch2010]. While typically only a 