10199 Chariklo

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"Chariklo" redirects here. For the Ancient Greek nymphs, see Chariclo.
10199 Chariklo
Chariklo with rings eso1410b.jpg
An artist's rendering of Chariklo with its rings
Discovery [1]
Discovered by James Scotti, Spacewatch
Discovery date 15 February 1997
Named after
1997 CU26
Orbital characteristics[1]
Epoch 27 June 2015 (JD 2457200.5)
Uncertainty parameter 1
Observation arc 26.51 yr (9,684 days)
Aphelion 18.495 AU
Perihelion 13.059 AU
15.777 AU
Eccentricity 0.1722
62.67 yr (22,890 days)
Inclination 23.408°
Known satellites 2 rings
undiscovered embedded or shepherd moons?[2]
Physical characteristics
Dimensions 254 km[2]
248±18 km[3]
302 km[1]
7.004 h [1][4]
Albedo 0.035±0.010[3]
Spectral type
SMASS = D, BR (G-mode)[4]
B−R=1.34 [4]
J−H=0.49 [4]
~18.3 [5]

10199 Chariklo (/ˈkærkl/ or /kəˈrɪkl/; Ancient Greek: Χαρικλώ; provisional designation: 1997 CU26) is the largest confirmed centaur (minor planet of the outer Solar System). It orbits the Sun between Saturn and Uranus, grazing the orbit of Uranus. On 26 March 2014, astronomers announced the discovery of two rings (nicknamed Oiapoque and Chuí),[6] around Chariklo by observing a stellar occultation.[7][8] making it the first known minor planet to have rings.[9]

Chariklo was discovered by James V. Scotti of the Spacewatch program on February 15, 1997. Chariklo is named after the nymph Chariclo (Χαρικλώ), the wife of Chiron and the daughter of Apollo.

A photometric study in 2001 was unable to find a definite period of rotation.[10] Infrared observations of Chariklo indicate the presence of water ice,[11] which may in fact be located in its rings.[2]

Michael Brown's website lists it as possibly a dwarf planet with a measured diameter of 232 km.[12]


Chariklo is currently the largest known centaur, with an estimated diameter of about 250 km (160 mi).[2] 2060 Chiron is likely to be the second largest with 220 km.[3] The lost centaur 1995 SN55 may even be larger, with an estimated diameter close to 300 km.[12]


Chariklo orbits within 0.09 AU of the 4:3 mean-motion resonance with Uranus.

Centaurs originated in the Kuiper belt and are in dynamically unstable orbits that will lead to ejection from the Solar System, an impact with a planet or the Sun, or transition into a short-period comet.[13]

The orbit of Chariklo is more stable than those of Nessus, Chiron, and Pholus. Chariklo lies within 0.09 AU of the 4:3 resonance of Uranus and is estimated to have a relatively long orbital half-life of about 10.3 Myr.[14] Orbital simulations of twenty clones of Chariklo suggest that Chariklo will not start to regularly come within 3 AU (450 Gm) of Uranus for about thirty thousand years.[15]

During the perihelic oppositions of 2003–04, Chariklo had an apparent magnitude of +17.7.[16] As of 2014, Chariklo was 14.8 AU from the Sun.[5]


Main article: Rings of Chariklo
Artist's impression of the rings around Chariklo.[7]

A stellar occultation in 2013 revealed that Chariklo has two rings, one about 7 and the other about 3 km wide,[6] being approximately 9 km apart,[17] at 396 and 405 km from Chariklo. This makes it the smallest known object to have rings. These rings are consistent with an edge-on orientation in 2008, which naturally explains Chariklo's dimming before 2008 and brightening since. Furthermore, it also naturally explains the gradual disappearance of the water-ice features in Chariklo's spectrum before 2008 and their reappearance thereafter if the water ice is in Chariklo's rings.[2][7][18]

The existence of a ring system around a minor planet was unexpected because it had been thought that rings could only be stable around much more massive bodies. Ring systems around minor bodies had not previously been discovered despite the search for them through direct imaging and stellar occultation techniques.[2] Chariklo's rings should disperse over a period of at most a few million years, so either they are very young, or they are actively contained by shepherd moons with a mass comparable to that of the rings.[2][7][18] The team nicknamed the rings Oiapoque (the inner, more substantial ring) and Chuí (the outer ring), after the two rivers that form the northern and southern coastal borders of Brazil. A request for formal names will be submitted to the IAU at a later date.[7]

2060 Chiron may have a similar pair of rings.[19]


  1. ^ a b c d "JPL Small-Body Database Browser: 10199 Chariklo (1997 CU26)" (2015-05-12 last obs.). Jet Propulsion Laboratory. Retrieved October 2015. 
  2. ^ a b c d e f g Braga-Ribas, F.; Sicardy, B.; Ortiz, J. L.; Snodgrass, C.; Roques, F.; Vieira-Martins, R.; Camargo, J. I. B.; Assafin, M.; Duffard, R.; Jehin, E.; Pollock, J.; Leiva, R.; Emilio, M.; Machado, D. I.; Colazo, C.; Lellouch, E.; Skottfelt, J.; Gillon, M.; Ligier, N.; Maquet, L.; Benedetti-Rossi, G.; Gomes, A. R.; Kervella, P.; Monteiro, H.; Sfair, R.; Moutamid, M. E.; Tancredi, G.; Spagnotto, J.; Maury, A.; et al. (2014-03-26). "A ring system detected around the Centaur (10199) Chariklo". Nature 508 (7494): 72–75. arXiv:1409.7259. Bibcode:2014Natur.508...72B. doi:10.1038/nature13155. PMID 24670644. 
  3. ^ a b c d Fornasier, S.; Lellouch, E.; Müller, T.; et al. (2013). "TNOs are Cool: A survey of the trans-Neptunian region. VIII. Combined Herschel PACS and SPIRE observations of 9 bright targets at 70–500 µm.". Astronomy & Astrophysics 555: A92. arXiv:1305.0449v2. Bibcode:2013A&A...555A..15F. doi:10.1051/0004-6361/201321329. 
  4. ^ a b c d e f g h i j Johnston's Archive for 10199 Chariklo
  5. ^ a b "AstDys (10199) Chariklo Ephemerides". Department of Mathematics, University of Pisa, Italy. Retrieved 2010-02-10. 
  6. ^ a b "Asteroid Chariklo's rings surprise astronomers". CBC News. 2014-03-26. Retrieved 2014-03-27. 
  7. ^ a b c d e "First Ring System Around Asteroid". ESO. 26 March 2014. Retrieved 2 April 2014. 
  8. ^ Woo, Marcus (26 March 2014). "First Asteroid With Rings Discovered". National Geographic. Retrieved 26 March 2014. 
  9. ^ "A second minor planet may possess Saturn-like rings". Space Daily. 17 March 2015. 
  10. ^ Peixinho; Doressoundiram (2000-11-09). "Photometric study of Centaurs 10199 Chariklo (1997CU26) and 1999UG5". Retrieved 2006-11-09. 
  11. ^ Jewitt; Brown (2001-04-17). "Infrared Observations of Centaur 10119 Chariklo with possible surface variation" (PDF). Retrieved 2006-11-09. 
  12. ^ a b Michael E. Brown. "How many dwarf planets are there in the outer solar system? (updates daily)". California Institute of Technology. Retrieved 2012-04-28. 
  13. ^ Sheppard, Scott S.; Jewitt, David C.; Trujillo, Chadwick A.; Brown, Michael J. I.; Ashley, Michael C. B. (2000). "A WIDE-FIELD CCD SURVEY FOR CENTAURS AND KUIPER BELT OBJECTS". The Astronomical Journal 120 (5): 2687–2694. arXiv:astro-ph/0008445. Bibcode:2000AJ....120.2687S. doi:10.1086/316805. Retrieved 2008-02-21. 
  14. ^ Horner, J.; Evans, N.W.; Bailey, M. E. (2004). "Simulations of the Population of Centaurs I: The Bulk Statistics". Monthly Notices of the Royal Astronomical Society 354 (3): 798–810. arXiv:astro-ph/0407400. Bibcode:2004MNRAS.354..798H. doi:10.1111/j.1365-2966.2004.08240.x. 
  15. ^ "Twenty clones of Centaur 10199 Chariklo making passes within 450Gm". Archived from the original on 2009-05-13. Retrieved 2009-05-09.  (Solex 10). Accessed 2009-05-10.
  16. ^ "AstDys (10199) Chariklo (March 2003) Ephemerides". Department of Mathematics, University of Pisa, Italy. Retrieved 2009-04-03. 
  17. ^ Elizabeth Landau (2014-03-26). "Astronomers find first asteroid with rings". CNN. Retrieved 2014-03-27. 
  18. ^ a b Gibney, E. (2014-03-26). "Asteroids can have rings too". Nature. doi:10.1038/nature.2014.14937. 
  19. ^ Ortiz, J.L.; Duffard, R.; Pinilla-Alonso, N.; Alvarez-Candal, A.; Santos-Sanz, P.; Morales, N.; Fernández-Valenzuela, E.; Licandro, J.; Campo Bagatin, A.; Thirouin, A. "Possible ring material around centaur (2060) Chiron". arXiv:1501.05911. 

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