2013 YP139 is a dark sub-kilometer asteroid on a highly eccentric orbit, classified as a near-Earth object and potentially hazardous asteroid of the Apollo group, approximately 400 meters (1,300 feet) in diameter. It was first observed as 2002 MU7 by NEAT at Palomar Observatory on 29 June 2002, and by the WISE space telescope on 29 December 2013, under its current, principal provisional designation. This object was the first possible discovery of the reinstated NEOWISE program of the WISE telescope, following the program's hibernation in 2011.