Finding activity cycles in Kepler data
1 : Konkoly Observatory
(MTA CSFK CSI)
* : Corresponding author
We analyse light curves of 39 fast-rotating active stars from the Kepler database. Using time-frequency analysis, we find proof for activity cycles of 400-900 days at 8 targets: the changing typical latitude of the starspots and the differential rotation of the stellar surface changes the observed rotation period.