Bondi spherical accretion

What you are seeing: a steady spherically symmetric accretion flow onto a point mass. Gas falls inward, passing through a sonic point at $r = r_B/2$ (isothermal). The Bondi rate $\dot M_B = \pi e^2 G^2 M^2 \rho_\infty / c_s^3$ sets the asymptotic accretion.