Volume 46 number 2 (2018)
We have measured the times of onset of recent fadings in four R Coronae Borealis (RCB) 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.