Virial equilibrium (source code)

= Virial equilibrium
{title2=$2K+W=0$}

A bounded gravitational system in statistical equilibrium satisfies the time-averaged <virial theorem>. For inverse-distance gravity with negligible boundary stresses, $2K+W=0$. This relation does not require static particles or a homogeneous density profile, and reaching it does not erase the system's dynamical history.