The data are also plotted in blue where the measured stretch is converted to $\mathcal{R}$(Si) with the top axis showing the scaling.[]{data-label="f:si_cavel"}](si_cavel){width="3.2in"}

Converting stretch to $\mathcal{R}$(Si), we can plot the measurements on Figure \[f:si\_cavel\]. The spectra do not cover the redder [Si$\,$]{} features, so a direct measurement could not be made. The values, which use a single Gaussian to fit the Ca H&K feature, span a similar range of  and inferred $\mathcal{R}$(Si) as the models, with the model trend going through the middle of the data values. The claimed trend of  with light-curve shape is clear using the values. However, this trend is similar to the trend generated by simply changing the temperature in the [SYNOW]{} models. We emphasize that the true  is fixed for all models and the  measured using a double-Gaussian fit varies only slightly over all models. The trend shown in Figure \[f:si\_cavel\] is solely the result of the method for measuring the velocity. The underlying physical effect is the changing strength of [Si$\,$]{} $\lambda 3858$ with temperature, and thus light-curve shape.

There will undoubtedly be a true range of velocities in the data. We have not explored how the [SYNOW]{} models change when varying several parameters, 