10199 Chariklo

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10199 Chariklo
Chariklo with rings eso1410b.jpg
An artist's rendering of Chariklo with its rings
Discovery
Discovered by James V. Scotti, Spacewatch
Discovery date February 15, 1997
Designations
Named after
Chariclo
1997 CU26
Minor planet category Centaur[1]
Orbital characteristics
Epoch November 25, 2005 (JD 2453700.0)
Aphelion 18.66 AU
Perihelion 13.08 AU
15.87 AU
Eccentricity 0.17534
63.17 yr (23,087.2 d)
10.6°
Inclination 23.375°
300.451°
242.361°
Known satellites 2 rings
undiscovered embedded or shepherd moons?[2]
Physical characteristics
Dimensions 248 ± 18 km[2]
258.6 ± 10.3 km[3]
Albedo 0.05–0.06[3]
Spectral type
B−V=0.84; V−R=0.50
~18.3[4]
6.6[1]

10199 Chariklo (/ˈkærɨkl/ KARR-i-kloh or /kəˈrɪkl/ kə-RIK-loh; 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)[5] around Chariklo by observing a stellar occultation.[6][7]

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.[8] Infrared observations of Chariklo indicate the presence of water ice,[9] 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.[10]

Size[edit]

Chariklo is currently the largest known centaur, with an estimated diameter of 250 km (160 mi).[2] 2060 Chiron is likely to be the second largest with 230 km.[3] The lost centaur 1995 SN55 may even be larger, with an estimated diameter close to 300 km.[10]

Orbit[edit]

Chariklo lies within 0.09 AU of the 4:3 resonance of 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.[11]

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 long orbital half-life of about 10.3 Myr.[12] 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.[13]

During the perihelic oppositions of 2003–4, Chariklo had an apparent magnitude of +17.7.[14] As of 2014, Chariklo is 14.8 AU from the Sun.[4]

Rings[edit]

Main article: Rings of Chariklo
Artist's impression of the rings around Chariklo.[15]

A stellar occultation in 2013 revealed that Chariklo has two rings, one about 7 and the other about 3 km wide,[5] being approximately 9 km apart,[16] at 396 and 405 km from Chariklo. This makes it the smallest known object to have rings. It appears that they are the source of the signature for water ice found in Chariklo's spectrum.[2][6][17]

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] It remains unclear how Chariklo could retain its rings over an extended period, but the existence of small shepherd moons may be invoked to confine the ring system.[2][6][17] 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.[6]

References[edit]

  1. ^ a b "JPL Small-Body Database Browser: 10199 Chariklo (1997 CU26)". 2008-07-03. Retrieved 2008-10-21. 
  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. doi:10.1038/nature13155. PMID 24670644.  edit
  3. ^ a b c John Stansberry, Will Grundy, Mike Brown, Dale Cruikshank, John Spencer, David Trilling, Jean-Luc Margot (2007). "Physical Properties of Kuiper Belt and Centaur Objects: Constraints from Spitzer Space Telescope". arXiv:0702538 [astro-ph].
  4. ^ a b "AstDys (10199) Chariklo Ephemerides". Department of Mathematics, University of Pisa, Italy. Retrieved 2010-02-10. 
  5. ^ a b "Asteroid Chariklo's rings surprise astronomers". CBC News. 2014-03-26. Retrieved 2014-03-27. 
  6. ^ a b c d "First Ring System Around Asteroid" (Press release). European Southern Observatory. 26 March 2014. Retrieved 2014-03-26. 
  7. ^ Woo, Marcus (26 March 2014). "First Asteroid With Rings Discovered". National Geographic. Retrieved 26 March 2014. 
  8. ^ Peixinho; Doressoundiram (2000-11-09). "Photometric study of Centaurs 10199 Chariklo (1997CU26) and 1999UG5". Retrieved 2006-11-09. 
  9. ^ Jewitt; Brown (2001-04-17). "Infrared Observations of Centaur 10119 Chariklo with possible surface variation". Retrieved 2006-11-09. 
  10. ^ 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. 
  11. ^ 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. 
  12. ^ 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. 
  13. ^ "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.
  14. ^ "AstDys (10199) Chariklo (March 2003) Ephemerides". Department of Mathematics, University of Pisa, Italy. Retrieved 2009-04-03. 
  15. ^ "First Ring System Around Asteroid". ESO. Retrieved 2 April 2014. 
  16. ^ Elizabeth Landau (2014-03-26). "Astronomers find first asteroid with rings". CNN. Retrieved 2014-03-27. 
  17. ^ a b Gibney, E. (2014-03-26). "Asteroids can have rings too". Nature. doi:10.1038/nature.2014.14937.  edit

External links[edit]