2017 XX61 is a small near-Earth object, approximately 17 meters (56 feet) in diameter that follows an eccentric orbit.
This Apollo asteroid was first observed on 15 December 2017, by astronomers of the Mount Lemmon Survey at Mount Lemmon Observatory near Tucson, Arizona.
[1] It transited Earth at 8 lunar distances on 18 December 2017 at 14:54 UTC, and was lost on the following night.
Its orbit has an eccentricity of 0.61 and an inclination of 8° with respect to the ecliptic.
[2] A generic magnitude-to-diameter conversion gives a mean-diameter of 13–27 meters, for an absolute magnitude of 26.6,[2] and an assumed albedo between 0.25 and 0.057, which typically correspond to the composition of a stony and carbonaceous body, respectively.