 Orbit ofRubincam (blue),inner planets andJupiter (outermost) | |
| Discovery[1] | |
|---|---|
| Discovered by | S. J. Bus |
| Discovery site | Siding Spring Obs. |
| Discovery date | 2 March 1981 |
| Designations | |
| (9921) Rubincam | |
Named after | David Rubincam (American geophysicist)[2] |
| 1981 EO18 | |
| main-belt · (inner)[3] | |
| Orbital characteristics[1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 63.45 yr (23,175 days) |
| Aphelion | 2.5174AU |
| Perihelion | 2.2352 AU |
| 2.3763 AU | |
| Eccentricity | 0.0594 |
| 3.66yr (1,338 days) | |
| 91.234° | |
| 0° 16m 8.76s / day | |
| Inclination | 2.4008° |
| 331.39° | |
| 89.205° | |
| Physical characteristics | |
| Dimensions | 4.10 km(calculated)[3] 4.250±0.094 km[4][5] |
| 8.01±0.03h[6] 8.014±0.0017 h[7] | |
| 0.20(assumed)[3] 0.204±0.035[4][5] | |
| S[3] | |
| 14.2[4] · 14.276±0.001(R)[7] · 14.3[1][3] | |
9921 Rubincam, provisional designation1981 EO18, is a stonyasteroid from the inner regions of theasteroid belt, approximately 4 kilometers in diameter. It was discovered on 2 March 1981, by American astronomerSchelte Bus at theSiding Spring Observatory in Australia, and later named after American geophysicistDavid Rubincam.[2]
Rubincam is a stonyS-type asteroid that orbits the Sun in theinner main-belt at a distance of 2.2–2.5 AU once every 3 years and 8 months (1,338 days). Its orbit has aneccentricity of 0.06 and aninclination of 2° with respect to theecliptic.[1]A firstprecovery was taken atPalomar Observatory in 1953, extending the body'sobservation arc by 28 years prior to its official discovery at Siding Spring.[2]
In February 2010, two rotationallightcurves ofRubincam were obtained from photometric observations at thePalomar Transient Factory in California. Lightcurve analysis gave arotation period of 8.01 and 8.014 hours with a brightness amplitude of 0.33 and 0.31 inmagnitude, respectively (U=3-/2).[6][7]
According to the survey carried out by NASA'sWide-field Infrared Survey Explorer with its subsequentNEOWISE mission,Rubincam measures 4.250 kilometers in diameter and its surface has analbedo of 0.204,[4][5] while theCollaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 4.1 kilometers with anabsolute magnitude of 14.3.[3]
Thisminor planet was named afterDavid Rubincam (born 1947), an American solid-earthgeophysicist and planetarygeodynamicist at NASA'sGoddard Space Flight Center in Greenbelt, Maryland. He was the first to study the influence of the radiation recoil effects on an asteroid's rotation period and spin axis, which he later named theYarkovsky–O'Keefe–Radzievskii–Paddack effect or YORP effect for short.[2] The official naming citation was published by theMinor Planet Center on 28 September 2015 (M.P.C. 95803).[8]
