18487 1996 AU3 is a main belt asteroid with an estimated diameter of 5 km. It was discovered on on January 13, 1996 by S. Ueda and H. Kaneda at Kushiro. The semi-major axis is 2.40 AU, the eccentricity is 0.180 and the inclination is 15.11 degrees.
Observations were made on six nights during the period from July 17 to August 18, 2002, using either 60 or 90 second exposures. A total of 312 observations were used in the solution. Analysis of the data showed a period of 6.512 hours.