  That the stellar halo of the Milky Way has a density profile which to first
approximation satisfies $\rho \propto r^{-3}$ has been known for a long time.
More recently, it has become clear that M31 also has such an extended stellar
halo, which approximately follows the same radial scaling. Studies of distant
galaxies have revealed the same phenomenology. Also, we now know that the
density profiles of the globular cluster systems of our Galaxy and Andromeda to
first approximation follow $\rho \propto r^{-3}$, $\Sigma \propto R^{-2}$ in
projection. Recently, diffuse populations of stars have been detected
spherically surrounding a number of Galactic globular clusters, extending much
beyond the Newtonian tidal radii, often without showing any evidence of tidal
features. Within the standard Newtonian and GR scenario, numerous and diverse
particular explanations have been suggested, individually tailored to each of
the different classes of systems described above. Here we show that in a
MONDian gravity scenario, any isothermal tenuous halo of tracer particles
forming a small perturbation surrounding a spherically symmetric mass
distribution, will have an equilibrium configuration which to first
approximation satisfies a $\rho \propto r^{-3}$ scaling.
