FM17p.14 — The potential of time-resolved frequency analysis: Quantification of period jitter and amplitude changes in OGLE LMC Cepheids

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Aug 10th at 6:00 PM until 6:00 PM

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Author(s): Maria Süveges2, Richard Irving Anderson1

Institution(s): 1. Johns Hopkins University, 2. University of Geneva

Recent years have seen a fast development in the modelling of stellar structures and evolution, parallelled by a similar vertiginous progress in the quality and quantity of collected data. This progress must be accompanied and supported by adequate statistical tools. In our talk, we revisit a technique of statistics called kernel modelling, and apply it to a group of OGLE-III Cepheids that exhibit nearby double peaks in their periodograms. These Cepheids are referred in the OGLE-III catalog as “Blazhko Cepheids”, although the relationship between the appearance of such double period peaks and the Blazhko effect is unclear. To investigate the phenomenology of these twin-peak Cepheids in more detail, we compare a sample of 31 LMC Cepheids that exhibit twin frequency peaks with 24 other Cepheids that do not. Using the kernel technique, we investigate the light curve variability as a function of time, revealing both frequency and amplitude modulations. We present the preliminary results of our study in progress, which sheds light at a complex interplay between both types of modulations and their detectability by twin peaks in the periodogram. The application reveals the potential of the kernel technique to help theory and modelling with detailed data analyses, capable of tracing fine time-dependent variations of the phenomenology of pulsations.