A Study of Pulsation and Fadings in some R Coronae Borealis Stars Article Swipe

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Stars Astrophysics Physics Amplitude Wavelet Optics Computer science Artificial intelligence

John R. Percy , Kevin H. Dembski ·

YOU? · · 2018 · Open Access · · DOI: https://doi.org/10.48550/arxiv.1809.04484 · OA: W2889778755

We have measured the times of onset of recent fadings in four R CrB stars -- V854 Cen, RY Sgr, R CrB, and S Aps. These times continue to be locked to the stars' pulsation periods, though with some scatter. In RY Sgr, the onsets of fading tend to occur at or a few days after pulsation maximum. We have studied the pulsation properties of RY Sgr through its recent long maximum using (O-C) analysis and wavelet analysis. The period "wanders" by a few percent. This wandering can be modelled by random cycle-to-cycle period fluctuations, as in some other types of pulsating stars. The pulsation amplitude varies between 0.05 and 0.25 in visual light, non-periodically but on a time scale of about 20 pulsation periods.