Stellar potential-energy tensor
= Stellar potential-energy tensor
{title2=$W_{ij}=-\int\rho x_i\partial_j\Phi\,d^3x$}
This force-moment tensor enters the <tensor virial theorem>. For an isolated self-gravitating population it is symmetric by pairwise interchange of the Newtonian interaction; for a tracer in an external field use the force-moment definition directly, with the appropriate symmetric combination in a time-dependent inertia identity.