eq.(\[lambda\]) and for $\lambda=1$. Dashed-dotted green line separates regions where the post-CE binary has more or less energy than at the start of the CE. Dotted green line separates regions where the post-CE is wider ($a>a_\mathrm{i}$) than at the start of the CE and where it shrunk ($a<a_\mathrm{i}$). \[alpha\] ](fig_alpha.eps){height=".36\textheight"}

As an example, we consider a binary with a giant of $2\,M_\odot$ and a WD of $0.5\,M_\odot$, where the CE is initiated when the giant has a radius of $21\,R_\odot$. The states of the binary system in the orbital-energy–angular-momentum ($E-J$) plane are plotted in Fig.\[alpha\]. The location of the initial state is marked with a star. For this state the orbital energy $E_\mathrm{orb, i}$ and the rotational energy of the giant’s envelope (assumed to be synchronized with the initial orbit), as well as the orbital angular momentum $J_\mathrm{orb, i}$ and angular momentum of the giant’s envelope are taken into account.

The thick solid line is determined by repeatedly removing the outermost mesh point from the structure model, assuming that the radius of the resulting star is equal to the radius coordinate the new outer mesh point had in the original model ([*i.e.*]{}, the model doesn’t expand), equating this radius to 