2007MNRAS.375..301C

Decline onset times were measured in long-term visual light curves for five R Coronae Borealis (RCB) variable stars. These included RYSgr and V854Cen, the two RCB stars previously reported to have a relationship between dust formation events and pulsational variations. Analysis of the decline epochs showed that all decline onsets for a given star obey a linear ephemeris tied to the object's dominant radial pulsation period. Thus, in addition to confirming the pulsation-decline correlation for RYSgr and V854Cen, this same behaviour was demonstrated in UWCen, RCrB and SAps for the first time. This general result firmly establishes the connection between radial pulsation and mass loss in the RCB stars. The dominant pulsation period of ~40d for all of these objects therefore represents the characteristic time-scale on which these stars produce dust.