Figure 5

Accuracy of fits to Roche radii. The difference between a cubic spline fit (see text for details) for \(R_{L1}\), \(R_{bk}\), \(R_{y}\), \(R_{z}\) and \(R_{eq}\) and the numerically calculated values, as a function of mass ratio q. Also shown is the difference between the Eggleton formula (\(R_{Egg}\)) and the accurate \(R_{eq}\), divided by 1,000. This shows that the spline fit is a factor of ∼10,000 better than the Eggleton formula for \(R_{eq}\). The vertical axis has been scaled up by a factor of 10⁶.