A photometric study in 2001 was unable to find a definite period of rotation.[27] Infrared observations of Chariklo indicate the presence of water ice,[28] which may in fact be located in its rings.[7]
A symbol derived from that for2060 Chiron,, was devised in the late 1990s by German astrologer Robert von Heeren. It replaces Chiron's K with a C for Chariklo.[29]
Chariklo is currently the largest knowncentaur, with a volume-equivalent diameter of about 250 km.[10] Its shape is probably elongated, with dimensions of 287.6 × 270.4 × 198.2 km.[10](523727) 2014 NW65 is likely to be the second largest with 225 km (140 mi) and2060 Chiron is likely to be the third largest with 220 km (140 mi).[8]
Centaurs originated in theKuiper belt and are in dynamically unstable orbits that will lead to ejection from the Solar System, animpact with a planet or the Sun, or transition into a short-periodcomet.[30]
The orbit of Chariklo is more stable than those ofNessus,Chiron, andPholus. Chariklo lies within 0.09 AU of the 4:3resonance of Uranus and is estimated to have a relatively long orbital half-life of about 10.3 Myr.[31] 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.[32]
A stellaroccultation in 2013[7][22] revealed that Chariklo has tworings with radii 386 and 400 km and widths of about 6.9 km and 0.12 km respectively.[10] The rings are approximately 14 km apart.[10] This makes Chariklo the smallest known object to have rings. These rings are consistent with an edge-on orientation in 2008, which can explain Chariklo's dimming before 2008 and brightening since. Nonetheless, the elongated shape of Chariklo explains most of the brightness variability resulting in darker rings than previously determined.[9] Furthermore, the rings can explain 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.[7][23][34]
An infographic showing the apparent brightness measurement during Chariklo's occultation
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.[7] 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 byshepherd moons with a mass comparable to that of the rings.[35][7][23][34] However, other research suggests that Chariklo's elongated shape combined with its fast rotation can clear material in an equatorial disk throughLindblad resonances and explain the survival and location of the rings, a mechanism valid also for the ring ofHaumea.[36]
The team nicknamed the ringsOiapoque (the inner, more substantial ring) andChuí (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 theIAU at a later date.[23]
Camilla is a mission concept published in June 2018 that would launch a robotic probe to perform a singleflyby of Chariklo and drop off a 100 kg (220 lb) impactor made oftungsten to excavate a crater approximately 10 m (33 ft) deep for remote compositional analysis during the flyby.[38] The mission would be designed to fit under the cost cap of NASA'sNew Frontiers program, although it has not been formally proposed to compete for funding. The spacecraft would be launched in September 2026, using one gravity assist from Venus in February 2027 and Earth in December 2027 and 2029 to accelerate it out toward Jupiter.
^abcdFornasier, S.; Lellouch, E.; Müller, T.; Santos-Sanz, P.; Panuzzo, P.; Kiss, C.; et al. (July 2013). "TNOs are Cool: A survey of the trans-Neptunian region. VIII. Combined Herschel PACS and SPIRE observations of nine bright targets at 70–500 μm".Astronomy and Astrophysics.555: 22.arXiv:1305.0449.Bibcode:2013A&A...555A..15F.doi:10.1051/0004-6361/201321329.S2CID119261700.
^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.
^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.
^Davies, John K.; McBride, Neil; Ellison, Sara L.; Green, Simon F.; Ballantyne, David R. (August 1998). "Visible and Infrared Photometry of Six Centaurs".Icarus.134 (2):213–227.Bibcode:1998Icar..134..213D.doi:10.1006/icar.1998.5931.
^Belskaya, I. N.; Bagnulo, S.; Barucci, M. A.; Muinonen, K.; Tozzi, G. P.; Fornasier, S.; et al. (November 2010). "Polarimetry of Centaurs (2060) Chiron, (5145) Pholus and (10199) Chariklo".Icarus.210 (1):472–479.Bibcode:2010Icar..210..472B.doi:10.1016/j.icarus.2010.06.005.
^Sicardy, B.; Leiva, R.; Renner, S.; Roques, F.; El Moutamid, M.; Santos-Sanz, P.; Desmars, J. (19 November 2018). "Ring dynamics around non-axisymmetric bodies with application to Chariklo and Haumea".Nature Astronomy.3 (2):146–153.arXiv:1811.09437.doi:10.1038/s41550-018-0616-8.ISSN2397-3366.S2CID119236027.
^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. (2015). "Possible ring material around centaur (2060) Chiron".Astronomy & Astrophysics.576: A18.arXiv:1501.05911.Bibcode:2015A&A...576A..18O.doi:10.1051/0004-6361/201424461.S2CID38950384.
^Howell, Samuel M.; Chou, Luoth; Thompson, Michelle; Bouchard, Michael C.; Cusson, Sarah; Marcus, Matthew L.; Smith, Harrison B.; Bhattaru, Srinivasa; Blalock, John J.; Brueshaber, Shawn; Eggl, Siegfried; Jawin, Erica R.; Miller, Kelly; Rizzo, Maxime; Steakley, Kathryn; Thomas, Nancy H.; Trent, Kimberly R.; Ugelow, Melissa; Budney, Charles J.; Mitchell, Karl L.; Lowes, Leslie (2018)."Camilla: A centaur reconnaissance and impact mission concept"(PDF).Planetary and Space Science.164:184–193.Bibcode:2018P&SS..164..184H.doi:10.1016/j.pss.2018.07.008.S2CID126013385.
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, was devised in the late 1990s by German astrologer Robert von Heeren. It replaces Chiron's K with a C for Chariklo.[29]
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