= Adiabatic apsidal condition
{title2=$|\dot\varpi/\dot\theta|\ll1$}
The signed instantaneous contribution of <apsidal precession> to azimuthal motion during <isotropic stellar mass loss> is $\dot\varpi/\dot\theta=-(\dot\mu/\mu n)(1-e^2)^{3/2}\sin f/[e(1+e\cos f)^2]$. Its maximum absolute magnitude is small when $n|\mu/\dot\mu|\gg F(e)$, where $F(e)\sim1/e$ near a circular orbit and $F(e)\to3\sqrt3/4$ as $e\to1$. The low-<orbital eccentricity> coordinate singularity can be avoided by evolving the <eccentricity vector>.
Back to article page
