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
Discovered by James V. Scotti, Spacewatch
Discovery date February 15, 1997
Named after
1997 CU26
Orbital characteristics
Epoch 2014-Dec-09 (JD 2457000.5)
Aphelion 18.47566 AU
Perihelion 13.053728 AU
15.76469 AU
Eccentricity 0.171964
62.59 yr (22,862.7 d)
Inclination 23.411389°
Known satellites 2 rings
undiscovered embedded or shepherd moons?[2]
Physical characteristics
Dimensions 248 ± 18 km[2]
258.6 ± 10.3 km[3]
302 ± 30 km[1]
7.004 h[1][4]
Albedo 0.05–0.06[3]
Spectral type
D (SMASSII), BR (G-mode)[4]

10199 Chariklo (/ˈkærɨkl/ 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]


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] Caltech astronomer Mike Brown's Web site lists it as possibly a dwarf planet with a measured diameter of 232 km.[12]




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


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 2003–4, 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.[17]

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,[18] 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][19]

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][19] 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.[20]


  4. ^ a b c d e f g h i j k Johnston's Archive for 10199 Chariklo
  9. ^ "A second minor planet may possess Saturn-like rings". Space Daily. 17 March 2015. 
  11. ^ Jewitt; Brown (2001-04-17). "Infrared Observations of Centaur 10119 Chariklo with possible surface variation" (PDF). Retrieved 2006-11-09. 
  20. ^ 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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