Upper panel: bivariate KDE of the logarithm of the weighted standard deviation of R₅ against median values of log for stars with more than five nights of observation. Redder colours indicate higher density. The white vertical line indicates the activity level of α Cen B. Lower panel: activity variability probability function for the α Cen B activity level. The vertical blue line marks the value of the weighted R₅ standard deviation of α Cen B obtained from the R₅ time series.