Quenching front in a fixed galactic potential

With test-parcel escape work $B(r)=-\Phi (r)$, outer gas in a spherical isolated attractive potential is less tightly bound and quenches first under identical local specific heating. A truncated inverse-square density gives $r_q=r_0\exp [1-q(e^{\nu t}-1)/(2k)]$ after edge onset. The result is a fixed-potential closure, not a self-consistent potential update after mass loss.