Mass loss rate
= Mass loss rate
{title2=$\dot M=-dM_\star/dt$}
The mass loss rate is the positive rate at which a body loses mass. For a steady spherical <stellar wind>, the <continuity equation> gives $\dot M=4\pi r^2\rho u_r$, constant across spheres enclosing the source. It is positive for outward radial flow; an accretion convention often uses a separate positive inward rate.