2017 FZ2 was discovered by American astronomer Gregory Leonard on March 19, 2017, observing for the Mt. Lemmon Survey from Mount Lemmon Observatory.[7][8] Its orbit is moderately eccentric (0.26), low inclination (1.81º) and a semi-major axis of 1.007 AU.[8] Upon discovery, it was classified as an Apolloasteroid but also an Earth crosser by the Minor Planet Center. Its orbit is very chaotic but it is relatively well determined; as of September 26, 2017, its orbit is based on 52 observations (1 Doppler) spanning a data-arc of 8 days.[2]2017 FZ2 has an absolute magnitude of 26.7 which gives a characteristic diameter of 20 m.[5]
2017 FZ2 was until very recently an Earth's coorbital, the sixth known quasi-satellite of our planet and the
smallest by far. Its most recent quasi-satellite episode may have started over 225 years ago and certainly ended after a close
encounter with the Earth on March 23, 2017.[6]
A number of other near-Earth asteroids move in orbits similar to that of 2017 FZ2, the largest being 54509 YORP. There is an apparent excess of small bodies moving in orbits similar to that of YORP and this could be the result of mass shedding from YORP.[6]
