Horseshoe orbit

However, the loop is not closed but drifts forward or backward so that the point it circles will appear to move smoothly along the larger body's orbit over a long period of time.

When the object approaches the larger body closely at either end of its trajectory, its apparent direction changes.

But Earth's gravity exerts an outward accelerating force, pulling the satellite into a higher orbit which (per Kepler's third law) decreases its angular speed.

Eventually, at Point C, the satellite reaches a high and slow enough orbit such that it starts to lag behind Earth.

This causes it to fall into a lower orbit, which actually increases the angular speed of the satellite around the Sun.

Bodies moving slowly on the trailing side of the planet will gain energy, rise to a higher, slower, orbit, and thereby fall behind, similarly repelled.

Thus a small body can move back and forth between a leading and a trailing position, never approaching too close to the planet that dominates the region.

Figure 1 above shows shorter orbits around the Lagrangian points L4 and L5 (e.g. the lines close to the blue triangles).

These are called tadpole orbits and can be explained in a similar way, except that the asteroid's distance from the Earth does not oscillate as far as the L3 point on the other side of the Sun.