small specific angular momentum and specific energy $E^2\gtrapprox{}A(r_0)$, can make up a spherical shell consisting of cold gas or fluid. For a distant observer, this shell would look like a shadow similar to that of a black hole. The existence of static degenerated orbits in other spacetimes is considered in [@Quevedo2011; @Pugliese2012; @Vieira2014; @Collodel2018]. We note also that in SFNS spacetimes, as opposed to black holes, a freely moving massive particle with $E\geq1$ will inevitably escape to infinity, while such a particle with $E<1$ will move on a bound geodesic; thus the value $E=1$ separates bound and unbound orbits.

Another important observational aspect of geodesic motion in the central regions of SFNSs is that orbits with sufficiently large $J$ can lie outside this shell and, at the same time, can have parameters which differ strongly from those for the corresponding orbits in vacuum and SFBHs spacetimes. For a given orbit in a SFNS spacetime, we are primarily interested in the angle of precession $\Delta\varphi$ of the orbit; the latter can be expressed as $$\label{precess}
\varphi_{\!{}_{\scriptscriptstyle osc}}=2J\!\int \limits_{\,r_{\!\scriptscriptstyle min}}^{\:r_{\!\scriptscriptstyle max}}\! \frac{\,\mathrm{e}^{\Phi}} {\,r^2\sqrt{E^2-V_{\!\scriptscriptstyle eff}\,}}\,dr\,,\quad \Delta\varphi\,=\,\varphi_{\!{}_{\scriptscriptstyle osc}}-2\pi\,,$$ where $r_{\!\scriptscriptstyle min}$ and $r_{\!\scriptscriptstyle max}$ are, respectively, the pericentre and apocentre radii. In other words, 