binary: the binary is *even less bound* than it was at the beginning — the same effect as having negative $\alpha$ or a stellar wind; apparently energy is generated during the mass removal to infinity. As a consequence, the binary is becomes wider during the mass loss. Speaking physically, it means that, if $\gamma=1.5$ can reconstruct some systems, in these systems the mass loss process was not conserving energy, and as such could not proceed on a dynamical-timescale and be called a common envelope. This is a clear indication of a stable mass transfer event and the MT phase has to be studied and understood using the appropriate tools.

![Orbital angular momentum and energy for a $2\,M_\odot + 1.5\,M_\odot$ binary ($r_\mathrm{d}=86\,R_\odot$ and $m_\mathrm{d,X}=0.38\,M_\odot$). Line styles are as in Fig.\[gamma1\]. \[gamma2\] ](fig_gamma2.eps){height=".36\textheight"}

Another example involves a binary with a smaller companion ($0.35\,M_\odot$, Fig.\[gamma3\]). Keplerian solutions can be found for $\gamma \approx 1.36-1.39$, where the largest acceptable solution is $\gamma\approx 1.415$. With $\gamma=1.5$, this binary has to extract so much angular momentum that the post-CE binary clearly has to merge if the realistic core sizes are taken into account, whereas energy consideration indicates that a merger is not necessary, though it is 