(55565) 2002 AW197

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(55565) 2002 AW197
Hubble Space Telescope image of 2002 AW197 taken in 2006
Discovered byPalomar Obs. (team)
Discovery sitePalomar Obs.
Discovery date10 January 2002
2002 AW197
TNO[3] · cubewano[4]
p-DP[5] · extended[6]
Orbital characteristics[3]
Epoch 31 May 2020 (JD 2459000.5)
Uncertainty parameter 3
Observation arc21.23 yr (7,756 d)
Earliest precovery date29 December 1997
Aphelion53.161 AU
Perihelion40.922 AU
47.042 AU
322.65 yr (117,848 d)
0° 0m 10.998s / day
≈ 5 May 2078[7]
±4 days
Physical characteristics
Mean diameter
768±39 km[8]
734±116 km[9]
700±50 km[10][11]
886 km[12]
8.87±0.01 h[13]
8.78±0.05 h[14]
8.86±0.01 h[15]
IR[16][17] · (moderately red)
B–V = 0.920±0.020[18]
V–R = 0.560±0.020[18]
V–I = 1.170±0.010[17]
20.0 (opposition)[19][20]
3.568±0.046 (V)[21]
3.156±0.059 (R)[22]
3.3 (assumed)[3]

(55565) 2002 AW197 (provisional designation 2002 AW197) is a classical, non-resonant trans-Neptunian object from the Kuiper belt in the outermost region of the Solar System, also known as a cubewano. With a likely diameter of at least 700 kilometers (430 miles), it is approximately tied with 2002 MS4 and 2013 FY27 (to within measurement uncertainties) as the largest unnamed object in the Solar System. It was discovered at Palomar Observatory in 2002.

Its rotation period is 8.8 hours and it is a moderately red color.[16] Tancredi notes that photometric observations suggest that it is a spheroid with a high albedo and small albedo spots.[23] However, its low albedo suggests it does not have planetary geology, as it should if it were a dwarf planet.


2002 AW197's orbit is outside that of Pluto's, with a higher inclination and different orientation


2002 AW197 was discovered on 10 January 2002, by astronomers at the Palomar Observatory in California.[1] Astronomers involved in the discovery were Michael Brown, Chad Trujillo, Eleanor Helin, Michael Hicks, Kenneth Lawrence and Steven H. Pravdo.[2] It is located near the Kuiper cliff.

Orbit and classification[edit]

2002 AW197 orbits the Sun at a distance of 40.9–53.2 AU once every 322.6 years (over 117,800 days; semi-major axis of 47 AU). Its orbit has an eccentricity of 0.13 and an inclination of 24° with respect to the ecliptic.[3] The body's observation arc begins with a precovery taken at Haleakala-NEAT/GEODSS (566) in December 1997, more than 4 years prior to its official discovery observation at Palomar.[1] At 45.4 AU from the Sun,[19] it continues to slowly approach the Sun until its perihelion passage at 41.1 AU in May 2078.[7]

Physical characteristics[edit]

2002 AW197 imaged by Spitzer on 13 April 2004

Combined observations of thermal emissions by the Herschel Space Observatory and Spitzer Space Telescope give a diameter of 768+39
and a geometric albedo of 0.112+0.012


ESO analysis of spectra reveals a strong red slope and no presence of water ice[24] (in contrast to Quaoar, also red) suggesting organic material (see comparison of colours and typical composition inferred from spectra of the TNOs).

See also[edit]


  1. ^ a b c d "55565 (2002 AW197)". Minor Planet Center. Retrieved 9 March 2018.
  2. ^ a b Marsden, Brian G. (20 July 2002). "MPEC 2002-O30 : 2002 AW197". IAU Minor Planet Center. Harvard-Smithsonian Center for Astrophysics. Retrieved 6 January 2010.
  3. ^ a b c d "JPL Small-Body Database Browser: 55565 (2002 AW197)" (2019-03-25 last obs.). Jet Propulsion Laboratory. 13 July 2019. Retrieved 20 February 2020.
  4. ^ "MPEC 2009-R09 :Distant Minor Planets (2009 SEPT. 16.0 TT)". IAU Minor Planet Center. 4 September 2009. Retrieved 4 October 2009.
  5. ^ Michael E. Brown. "How many dwarf planets are there in the outer solar system? (updates daily)". California Institute of Technology. Retrieved 31 August 2016.
  6. ^ Marc W. Buie. "Orbit Fit and Astrometric record for 55565" (2009-03-23 using 112 observations). SwRI (Space Science Department). Retrieved 4 October 2009.
  7. ^ a b JPL Horizons Observer Location: @sun (Perihelion occurs when deldot changes from negative to positive. Uncertainty in time of perihelion is 3-sigma.)
  8. ^ a b c Vilenius, E.; Kiss, C.; Müller, T.; Mommert, M.; Santos-Sanz, P.; Pál, A.; et al. (April 2014). ""TNOs are Cool": A survey of the trans-Neptunian region. X. Analysis of classical Kuiper belt objects from Herschel and Spitzer observations". Astronomy and Astrophysics. 564: 18. arXiv:1403.6309v1. Bibcode:2014A&A...564A..35V. doi:10.1051/0004-6361/201322416. S2CID 118513049.
  9. ^ Stansberry, J.; Grundy, W.; Brown, M.; Cruikshank, D.; Spencer, J.; Trilling, D.; et al. (December 2007). "Physical Properties of Kuiper Belt and Centaur Objects: Constraints from the Spitzer Space Telescope". The Solar System Beyond Neptune: 161–179. arXiv:astro-ph/0702538. Bibcode:2008ssbn.book..161S.
  10. ^ Stansberry, J. A.; Cruikshank, D. P.; Grundy, W. G.; Margot, J. L.; Emery, J. P.; Fernandez, Y. R.; et al. (August 2005). "Albedos, Diameters (and a Density) of Kuiper Belt and Centaur Objects". American Astronomical Society. 37: 737. Bibcode:2005DPS....37.5205S.
  11. ^ Cruikshank, Dale P.; Stansberry, John A.; Emery, Joshua P.; Fernández, Yanga R.; Werner, Michael W.; Trilling, David E.; et al. (May 2005). "The High-Albedo Kuiper Belt Object (55565) 2002 AW197". The Astrophysical Journal. 624 (1): L53–L56. Bibcode:2005ApJ...624L..53C. doi:10.1086/430420.
  12. ^ Grundy, W. M.; Noll, K. S.; Stephens, D. C. (July 2005). "Diverse albedos of small trans-neptunian objects". Icarus. 176 (1): 184–191. arXiv:astro-ph/0502229. Bibcode:2005Icar..176..184G. doi:10.1016/j.icarus.2005.01.007. S2CID 118866288.
  13. ^ Lellouch, E.; Santos-Sanz, P.; Lacerda, P.; Mommert, M.; Duffard, R.; Ortiz, J. L.; et al. (September 2013). ""TNOs are Cool": A survey of the trans-Neptunian region. IX. Thermal properties of Kuiper belt objects and Centaurs from combined Herschel and Spitzer observations". Astronomy & Astrophysics. 557 (A60): 19. arXiv:1403.6309. Bibcode:2013A&A...557A..60L. doi:10.1051/0004-6361/201322416.
  14. ^ Thirouin, A.; Ortiz, J. L.; Duffard, R.; Santos-Sanz, P.; Aceituno, F. J.; Morales, N. (November 2010). "Short-term variability of a sample of 29 trans-Neptunian objects and Centaurs". Astronomy and Astrophysics. 522: 43. arXiv:1004.4841. Bibcode:2010A&A...522A..93T. doi:10.1051/0004-6361/200912340. S2CID 54039561.
  15. ^ Ortiz, J. L.; Gutiérrez, P. J.; Santos-Sanz, P.; Casanova, V.; Sota, A. (March 2006). "Short-term rotational variability of eight KBOs from Sierra Nevada Observatory". Astronomy and Astrophysics. 447 (3): 1131–1144. Bibcode:2006A&A...447.1131O. doi:10.1051/0004-6361:20053572.
  16. ^ a b "LCDB Data for (55565)". Asteroid Lightcurve Database (LCDB). Retrieved 9 March 2018.
  17. ^ a b Belskaya, Irina N.; Barucci, Maria A.; Fulchignoni, Marcello; Dovgopol, Anatolij N. (April 2015). "Updated taxonomy of trans-neptunian objects and centaurs: Influence of albedo". Icarus. 250: 482–491. Bibcode:2015Icar..250..482B. doi:10.1016/j.icarus.2014.12.004.
  18. ^ a b Tegler, S. C.; Romanishin, W.; Consolmagno, G. J.; J., S. (December 2016). "Two Color Populations of Kuiper Belt and Centaur Objects and the Smaller Orbital Inclinations of Red Centaur Objects". The Astronomical Journal. 152 (6): 13. Bibcode:2016AJ....152..210T. doi:10.3847/0004-6256/152/6/210. S2CID 125183388.
  19. ^ a b "AstDys (55565) 2002AW197 Ephemerides". Department of Mathematics, University of Pisa, Italy. Retrieved 14 December 2013.
  20. ^ "HORIZONS Web-Interface". JPL Solar System Dynamics. Retrieved 2 July 2008.
  21. ^ Vilenius, E.; Kiss, C.; Müller, T.; Mommert, M.; Santos-Sanz, P.; Pál, A.; et al. (April 2014). ""TNOs are Cool": A survey of the trans-Neptunian region X. Analysis of classical Kuiper belt objects from Herschel and Spitzer observations". Astronomy & Astrophysics. 564 (A35): 18. arXiv:1403.6309. Bibcode:2014A&A...564A..35V. doi:10.1051/0004-6361/201322047.
  22. ^ Peixinho, N.; Delsanti, A.; Guilbert-Lepoutre, A.; Gafeira, R.; Lacerda, P. (October 2012). "The bimodal colors of Centaurs and small Kuiper belt objects". Astronomy and Astrophysics. 546: 12. arXiv:1206.3153. Bibcode:2012A&A...546A..86P. doi:10.1051/0004-6361/201219057. S2CID 55876118.
  23. ^ Tancredi, G., & Favre, S. (2008) Which are the dwarfs in the Solar System?. Depto. Astronomía, Fac. Ciencias, Montevideo, Uruguay; Observatorio Astronómico Los Molinos, MEC, Uruguay. Retrieved 10-08-2011
  24. ^ D. Ragozzine; M. E. Brown (2007). "Candidate Members and Age Estimate of the Family of Kuiper Belt Object 2003 EL61". The Astronomical Journal. 134 (6): 2160–2167. arXiv:0709.0328. Bibcode:2007AJ....134.2160R. doi:10.1086/522334. S2CID 8387493.

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