The multiperiodicity of the $γ$ Doradus stars HD 224945 and HD 224638 as detected from a multisite campaign

Abstract

We discuss new photometric data collected on the gamma Dor variables HD 224945 and HD 224638. Multiperiodicity was detected in both stars, thanks to the clear spectral window of a multisite campaign that involved five observatories. HD 224945 shows the shortest period among the gamma Dor stars, i.e., 0.3330 d. The pulsation behaviour is very different: HD 224945 displays a set of frequencies spread over an interval much wider than that of HD 224638. We clearly found evidence for amplitude variations in the excited modes by comparing data from different years. HD 224945 and HD 224638 are among the best examples of $γ$ Dor stars that show multimode pulsations, which make them very interesting from an asteroseismological point of view.