5256 Farquhar

5256 Farquhar
Discovery [1]
Discovered by E. F. Helin
C. Mikolajczak
R. Coker
Discovery site Palomar Obs.
Discovery date 11 July 1988
Designations
MPC designation 5256 Farquhar
Named after
 Robert W. Farquhar
(NASA )[2]
1988 NN · 1955 HK
main-belt · Eunomia [3]
Orbital characteristics [1]
Epoch 31 July 2016 (JD 2457600.5)
Uncertainty parameter 0
Observation arc 61.14 yr (22,331 days)
Aphelion 3.0629 AU
Perihelion 2.0427 AU
2.5528 AU
Eccentricity 0.1998
4.08 yr (1,490 days)
309.85°
0° 14m 29.76s / day
Inclination 14.955°
219.35°
88.771°
Physical characteristics
Dimensions 11.990±0.126 km[4]
12.09 km (calculated)[3]
12.949±0.140 km[5]
11.513±0.001 h[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 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.[8]

    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.[1] 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.[8]

    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 11.513±0.001 hours with a very low brightness variation of 0.07 in magnitude (U=2).[6] 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.[4][5] 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.[3]

    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.[2] Naming citation was published on 10 November 1992 (M.P.C. 21134).[9]

    References

    1. 1 2 3 4 "JPL Small-Body Database Browser: 5256 Farquhar (1988 NN)" (2016-06-16 last obs.). Jet Propulsion Laboratory. Retrieved 9 September 2016.
    2. 1 2 Schmadel, Lutz D. (2007). Dictionary of Minor Planet Names – (5256) Farquhar. Springer Berlin Heidelberg. p. 451. ISBN 978-3-540-00238-3. Retrieved 9 September 2016.
    3. 1 2 3 4 5 6 "LCDB Data for (5256) Farquhar". Asteroid Lightcurve Database (LCDB). Retrieved 9 September 2016.
    4. 1 2 3 Masiero, Joseph R.; Grav, T.; Mainzer, A. K.; Nugent, C. R.; Bauer, J. M.; Stevenson, R.; et al. (August 2014). "Main-belt Asteroids with WISE/NEOWISE: Near-infrared Albedos". The Astrophysical Journal. 791 (2): 11. arXiv:1406.6645Freely accessible. Bibcode:2014ApJ...791..121M. doi:10.1088/0004-637X/791/2/121. Retrieved 9 September 2016.
    5. 1 2 3 4 Mainzer, A.; Grav, T.; Masiero, J.; Hand, E.; Bauer, J.; Tholen, D.; et al. (November 2011). "NEOWISE Studies of Spectrophotometrically Classified Asteroids: Preliminary Results" (PDF). The Astrophysical Journal. 741 (2): 25. arXiv:1109.6407Freely accessible. Bibcode:2011ApJ...741...90M. doi:10.1088/0004-637X/741/2/90. Retrieved 9 September 2016.
    6. 1 2 Odden, Caroline E.; Bond, J. Brooke; Aggarwal, Ashok K.; Seokjun, Yoon; Chapman, Kathryn J.; Fortin, Liam G.; et al. (October 2014). "Lightcurve Analysis for Three Asteroids: 4000 Hipparchus, 5256 Farquhar and 5931 Zhvanetskij". The Minor Planet Bulletin. 41 (4): 274–275. Bibcode:2014MPBu...41..274O. ISSN 1052-8091. Retrieved 9 September 2016.
    7. ↑ Veres, Peter; Jedicke, Robert; Fitzsimmons, Alan; Denneau, Larry; Granvik, Mikael; Bolin, Bryce; et al. (November 2015). "Absolute magnitudes and slope parameters for 250,000 asteroids observed by Pan-STARRS PS1 - Preliminary results". Icarus. 261: 34–47. arXiv:1506.00762Freely accessible. Bibcode:2015Icar..261...34V. doi:10.1016/j.icarus.2015.08.007. Retrieved 9 September 2016.
    8. 1 2 "5256 Farquhar (1988 NN)". Minor Planet Center. Retrieved 9 September 2016.
    9. ↑ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 9 September 2016.

    External links

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