Heliocentric radial velocities of R CrB

There are four principal sources: the Lick Observatory (1950 to 1953), the original Cambridge radial-velocity spectrometer (1968 to 1991), and the Haute-Provence and Cambridge Coravels (1986 to 1998 and 1997 to 2007, respectively). In the case of the last set the size (equivalent width) and width (expressed as if Vsin(i)) of the Coravel cross-correlation (dip) profiles are also given, and the variation and complexity of those profiles are discussed.

Although there is often evidence of cyclical behaviour in radial velocity, no coherent periodicity is found in any of the series. From time to time, and especially over 100 days before the great decline of 2007, the atmosphere was highly disturbed, with evidence of high-velocity components. We suggest that those are associated with large turbulent elements and result in mass ejection to sufficient distances for the formation of soot and other solids and thus the initiation of RCB-type declines.