Rosetta orbit

A retrograde Newtonian shift can occur when the central mass is extended rather than a point gravitational source, resulting in a non-closed orbit.

A prograde relativistic shift happens because of relativistic effects from a massive gravitational source.

[2] An object approaching a black hole with an intermediate velocity (not slow enough to spiral into the hole and not fast enough to escape) enters a complex orbit pattern, bounded by a near and far distance to the hole and tracing an oscillating pattern known as a hypotrochoid.

In 2020, scientists using observations made by the European Southern Observatory's Very Large Telescope revealed for the first time that star S2 orbits in this pattern around Sagittarius A*.

[3][4] In quantum mechanics, the Rosetta orbit is a solution for spherically symmetric (except 1/r) potentials.