Fixed-energy virial constraint between steady states
= Fixed-energy virial constraint between steady states
{title2=$T=-E,\quad W=2E$}
Two finite isolated steady gravitational systems at the same conserved energy obey $2T+W=0$ at each endpoint, so both have $T=-E$ and $W=2E$. Redistribution can increase central concentration without making the global potential energy more negative. Escaping matter or an external reservoir requires a different energy accounting.