| Discovery [1] | |
|---|---|
| Discovered by | H. E. Holt |
| Discovery site | Palomar Obs. |
| Discovery date | 27 July 1990 |
| Designations | |
| (5642) Bobbywilliams | |
Named after | Bobby G. Williams (JPL engineer)[2] |
| 1990 OK1 | |
| Mars-crosser [1][3][4] | |
| Orbital characteristics [1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 41.97 yr (15,330 days) |
| Aphelion | 3.0867AU |
| Perihelion | 1.5454 AU |
| 2.3161 AU | |
| Eccentricity | 0.3327 |
| 3.52yr (1,287 days) | |
| 235.13° | |
| 0° 16m 46.56s / day | |
| Inclination | 24.956° |
| 310.12° | |
| 39.038° | |
| Physical characteristics | |
| Dimensions | 4.71 km(calculated)[4] |
| 4.8341±0.0003h[5] | |
| 0.20(assumed)[4] | |
| S [4] | |
| 14.0[1][4] · 14.24±0.23[6] | |
5642 Bobbywilliams, provisional designation1990 OK1, is an eccentric, stonyasteroid andMars-crosser from the inner regions of theasteroid belt, approximately 4.7 kilometers in diameter.
It was discovered on 27 July 1990, by American astronomerHenry E. Holt atPalomar Observatory in California, United States.[3] The asteroid was named for JPL engineerBobby Williams.[2]
Bobbywilliams orbits the Sun in theinner main-belt at a distance of 1.5–3.1 AU once every 3 years and 6 months (1,287 days). Its orbit has aneccentricity of 0.33 and aninclination of 25° with respect to theecliptic.[1] A firstprecovery was taken at the AustralianSiding Spring Observatory in 1975, extending the body'sobservation arc by 15 years prior to its official discovery at Palomar.[3]
In July 2011, a rotationallightcurve ofBobbywilliams was obtained from photometric observations by astronomer Julian Oey at both the Australian Kingsgrove (E19) and Leura (E17) observatories. Lightcurve analysis gave a well-definedrotation period of4.8341 hours with a brightness variation of 0.05magnitude (U=3).[5]
TheCollaborative Asteroid Lightcurve Link assumes a standard albedo forstony asteroids of 0.20 and calculates a diameter of 4.71 kilometers with anabsolute magnitude of 14.0.[4]
Thisminor planet was named forJet Propulsion Laboratory engineer Bobby G. Williams (born 1951), specialized incelestial mechanics and the navigation ofspace probes. He has been a leading navigation manager whenNEAR Shoemaker had its rendezvous with the asteroids253 Mathilde and433 Eros,[2] The official naming citation was published by theMinor Planet Center on 28 July 1999 (M.P.C. 35483).[7]
