[4] It was first observed on 27 November 2016 by NEOWISE, the asteroid-and-comet-hunting portion of the Wide-Field Infrared Survey Explorer (WISE) mission.

[5] 2016 WF9 is about 0.5–1.0 km (0.3–0.6 mi) across so is one of the larger potentially hazardous asteroid near-Earth object (also see list of largest PHAs).

[4] 2016 WF9 passed Earth on 25 February 2017 at a distance of 0.3407 AU (50,970,000 km; 31,670,000 mi) and is not considered a threat for the foreseeable future.

[6] As the observation arc became longer and the orbital parameters better constrained, it was removed from the Sentry Risk Table on 20 December 2016.

[2] A simulation of 2016 WF9's dynamics over a period of 100 million days (~274,000 years) found that it had roughly a 60% chance of originating from the outer Solar System as a long-period comet.