Discovered by H. E. Holt MPC designation 5642 Bobbywilliams Minor planet category Mars-crosser Aphelion 3.09 m Orbits Sun | Discovery date 27 July 1990 Alternative names 1990 OK1 Discovered 27 July 1990 Inclination 24.968° | |
Named after Bobby G. Williams(JPL staff member) | ||
5642 Bobbywilliams, provisional designation 1990 OK1, is an eccentric stony asteroid and Mars-crosser from the inner regions of the asteroid belt, approximately 4.7 kilometers in diameter. It was discovered by American astronomer Henry E. Holt at the U.S. Palomar Observatory, California, on 27 July 1990.
The S-type asteroid orbits the Sun at a distance of 1.5–3.1 AU once every 3 years and 6 months (1,287 days). Its orbit has an eccentricity of 0.33 and an inclination of 25° with respect to the ecliptic. The first precovery was taken at the Australian Siding Spring Observatory in 1975, extending the asteroid's observation arc by 15 years prior to its discovery.
A rotational light-curve for this asteroid was obtained from photometric observations by astronomer Julian Oey at both the Australian Kingsgrove and Leura observatories in July 2011. It gave a well-defined rotation period of 7000483410000000000♠4.8341±0.0003 hours with a brightness variation of 0.05 in magnitude (U=3). The Collaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 4.71 kilometers.
The minor planet was named for Jet Propulsion Laboratory engineer Bobby G. Williams (b. 1951), specialized in celestial mechanics and the navigation of space probes. He has been a leading navigation manager when NEAR Shoemaker had its rendezvous with the asteroids 253 Mathilde and 433 Eros, Naming citation was published on 28 July 1999 (M.P.C. 35483).