title: 2017 XX61
text: # 2017 XX61
  
  2017 $XX_{61}$ is a small near-Earth object, approximately 17 meters (56 feet) in diameter, that transited Earth at 8 lunar distances on 18 December 2017 at 14:54 UTC. The Apollo asteroid on an eccentric orbit was first observed by the Mount Lemmon Survey and was lost on the following night. As of 2020, it has not been recovered.
  
  ## Description
  
  2017 $XX_{61}$ was first observed on 15 December 2017, by astronomers of the Mount Lemmon Survey at Mount Lemmon Observatory near Tucson, Arizona.
  
  It orbits the Sun at a distance of 0.8–3.3 AU once every 2 years and 11 months (1,062 days; semi-major axis of 2.04 AU). Its orbit has an eccentricity of 0.61 and an inclination of 8° with respect to the ecliptic.
  
  2017 $XX_{61}$ has an Earth minimum orbital intersection distance of 0.0162 AU (2,420,000 km), which translates into 6.3 lunar distances. The asteroid also approached Mars on 11 May 2018.
  
  A generic magnitude-to-diameter conversion gives a mean-diameter of 13–27 meters, for an absolute magnitude of 26.6, and an assumed albedo between 0.25 and 0.057, which typically correspond to the composition of a stony and carbonaceous body, respectively.
  
  