Discovery date 11 July 1988 Alternative names 1988 NN · 1955 HK Discovered 11 July 1988 Discoverer Eleanor F. Helin Discovery site Palomar Observatory | MPC designation 5256 Farquhar Minor planet category main-belt · Eunomia Orbits Sun Asteroid family Eunomia family Asteroid group Asteroid belt | |
Discovered by E. F. Helin
C. Mikolajczak
R. Coker Named after Robert W. Farquhar
(NASA ) Similar 4015 Wilson–Harrington, Sun, 85 Io | ||
5256 Farquhar, provisional designation 1988 NN, is a stony Eunomian asteroid from the middle regions of the asteroid belt, approximately 12 kilometers in diameter. It was discovered on 11 July 1988, by American astronomers Eleanor Helin, Celina Mikolajczak and Robert Coker at the Palomar Observatory in California.
The asteroid is a member of the Eunomia family, the most prominent family in the intermediate main-belt, which mostly consists of stony S-type asteroids. It orbits the Sun at a distance of 2.0–3.1 AU once every 4 years and 1 month (1,490 days). Its orbit has an eccentricity of 0.20 and an inclination of 15° with respect to the ecliptic. The first observation was made at the U.S. Goethe Link Observatory in 1955, extending the asteroid's observation arc by 33 years prior to its discovery.
In November 2013, a rotational light-curve was obtained for this asteroid from photometric observations at the Phillips Academy Observatory (I12), Massachusetts, and at the HUT Observatory (H16), Colorado. The bimodal light-curve gave a rotation period of 7001115130000000000♠11.513±0.001 hours with a very low brightness variation of 0.07 in magnitude (U=2). A low brightness amplitude typically indicates a rather spheroidal shape.
According to the surveys carried out by NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, the asteroid measures 12.0 and 12.9 kilometers in diameter and its surface has an albedo of 0.148 and 0.128, respectively. The Collaborative 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, based on an absolute magnitude of 11.9.
The minor planet was named for American NASA mission design specialist Robert W. Farquhar (1932–2015). At the Goddard Space Flight Center, he designed low-cost spacecrafts and missions to explore the Solar System. He was known for his international collaborations and for designing missions to comets and minor planets using inventive alternative trajectories. Naming citation was published on 10 November 1992 (M.P.C. 21134).