(309239) 2007 RW10, also written (309239) 2007 RW10, is a temporary quasi-satellite of Neptune. Observed from Neptune, it would appear to go around it during one Neptunian year but it actually orbits the Sun, not Neptune.
Read more about (309239) 2007 RW10: Discovery, Orbit and Physical Properties, Quasi-satellite Dynamical State and Orbital Evolution, Origin, See Also