| Discovery [1] | |
|---|---|
| Discovered by | E. F. Helin C. Mikolajczak R. Coker |
| Discovery site | Palomar Obs. |
| Discovery date | 11 July 1988 |
| Designations | |
| (5256) Farquhar | |
Named after | Robert W. Farquhar (NASA specialist)[2] |
| 1988 NN · 1955 HK | |
| main-belt · Eunomia [3] | |
| Orbital characteristics [1] | |
| Epoch 4 September 2017 (JD 2458000.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 61.27 yr (22,379 days) |
| Aphelion | 3.0639AU |
| Perihelion | 2.0426 AU |
| 2.5532 AU | |
| Eccentricity | 0.2000 |
| 4.08yr (1,490 days) | |
| 46.478° | |
| 0° 14m 29.76s / day | |
| Inclination | 14.956° |
| 219.35° | |
| 88.805° | |
| Physical characteristics | |
| Dimensions | 11.990±0.126km[4] 12.09 km(calculated)[3] 12.949±0.140 km[5] |
| 11.513±0.001h[6] | |
| 0.1275±0.0198[5] 0.148±0.020[4] 0.21(assumed)[3] | |
| S [3] | |
| 11.8[1] · 11.9[3] · 12.3[5] · 12.41±0.63[7] | |
5256 Farquhar, provisional designation1988 NN, is a stony Eunomianasteroid from the middle regions of theasteroid belt, approximately 12 kilometers in diameter. It was discovered on 11 July 1988, by American astronomersEleanor Helin,Celina Mikolajczak andRobert Coker at thePalomar Observatory in California.[8] The asteroid was later named for American NASA specialistRobert W. Farquhar.[2]
Farquhar is a member of theEunomia family, the most prominent family in the intermediate main-belt, which mostly consists of stonyS-type asteroids. It orbits the Sun in thecentral main-belt at a distance of 2.0–3.1 AU once every 4 years and 1 month (1,490 days). Its orbit has aneccentricity of 0.20 and aninclination of 15° with respect to theecliptic.[1] The first observation was made at the U.S.Goethe Link Observatory in 1955, extending the asteroid'sobservation arc by 33 years prior to its discovery.[8]
In November 2013, a rotationallightcurve ofFarquhar was obtained fromphotometric observations at the Phillips Academy Observatory (I12), Massachusetts, and at the HUT Observatory (H16), Colorado. The bimodal lightcurve gave arotation period of11.513 hours with a very low brightness variation of 0.07 inmagnitude (U=2).[6] A low brightness amplitude typically indicates a ratherspheroidal shape.
According to the surveys carried out by NASA'sWide-field Infrared Survey Explorer with its subsequentNEOWISE mission,Farquhar measures 12.0 and 12.9 kilometers in diameter and its surface has analbedo of 0.148 and 0.128, respectively.[4][5] TheCollaborative Asteroid Lightcurve Link assumes an albedo of 0.21, derived from the family's largest member and namesake,15 Eunomia, and calculates a diameter of 12.1 kilometers with anabsolute magnitude of 11.9.[3]
Thisminor planet was named for AmericanNASA mission design specialistRobert W. Farquhar (1932–2015). At theGoddard Space Flight Center, he designed low-cost spacecraft and missions to explore theSolar System.[2]
Farquhar was known for his international collaborations and for designing missions to comets and minor planets using inventive alternative trajectories.[2] The approved naming citation was published by theMinor Planet Center on 10 November 1992 (M.P.C. 21134).[9]
