On 2018 May 30, 12:02 UT, the 249.1 km diameter asteroid (10199) Chariklo will occult the 14.9 mag star 2UCAC 20036612 in the constellation Sagittarius for observers along a path across possibly New Zealand, Australia.
Title: The structure of Chariklo's rings from stellar occultations Author: D. Bérard, B. Sicardy, J.I.B. Camargo, J. Desmars, F. Braga-Ribas, J.L. Ortiz, R. Duffard, N. Morales, E. Meza, R. Leiva Espinoza, G. Benedetti-Rossi, M. Assafin, R. Vieira-Martins, F. Colas, J.L. Dauvergne, P. Kervella, J. Lecacheux, L. Maquet, F. Vachier, A.A. Sickafoose, H. Breytenbach, A. Genade, W. Beisker, K.L. Bath, H.J. Bode, V.D. Ivanov, E. Jehin, J. Pollock, G. Tancredi, S. Roland, R. Salvo, L. Vanzi, D. Herald, D. Gault, S. Kerr, H. Pavlov, K.M. Hill, J. Bradshaw, M.A. Barry, A. Cool, B. Lade, A. Cole, B. Giles, J. Broughton, J. Newman, R. Horvart, D. Maybour, D. Giles, L. Davis, R.A. Paton, B. Loader, A. Pennell, P.D. Jaquiery, S. Brillant, F. Selman, C. Dumas, C. Herrera, G. Carraro, L. Monaco, A. Maury, A. Peyrot, J.P. Teng, A. Richichi, P. Irawati, C. De Witt, P. Schoenau, et al. (13 additional authors not shown)
Two narrow and dense rings (called C1R and C2R) were discovered around the Centaur object (10199) Chariklo during a stellar occultation observed on June 3, 2013 (Braga-Ribas et al. 2014). Following this discovery, we have planned observations of several occultations by Chariklo's system in order to better characterize the ring and main body physical properties. Here, we use 12 successful Chariklo's occultations observed between 2014 and 2016. They provide ring profiles (physical width, opacity, edge structure) and constraints on their radii and pole position. Our new observations are currently consistent with the circular ring solution and pole position, to within the ± 3.3 km formal uncertainty for the ring radii, derived by Braga-Ribas et al. (2014). The six resolved C1R profiles reveal significant width variations from ~ 5.5 to 7 km. The width of the fainter ring C2R is less constrained, and may vary between 0.1 and 1 km. The inner and outer edges of C1R are consistent with infinitely sharp boundaries, with typical upper limits of one kilometer for the transition zone between the ring and empty space. No constraint on the sharpness of C2R's edges is available. A 1 sigma upper limit of ~ 20 m is derived for the equivalent width of narrow (physical width < 4 km) rings up to distances of 12,000 km, counted in the ring plane.
Title: The Dynamical History of Chariklo and its Rings Author: Jeremy Wood, Jonti Horner, Tobias C. Hinse, Stephen C. Marsden
Chariklo is the only small Solar system body confirmed to have rings. Given the instability of its orbit, the presence of rings is surprising, and their origin remains poorly understood. In this work, we study the dynamical history of the Chariklo system by integrating almost 36,000 Chariklo clones backwards in time for one Gyr under the influence of the Sun and the four giant planets. By recording all close encounters between the clones and planets, we investigate the likelihood that Chariklo's rings could have survived since its capture to the Centaur population. Our results reveal that Chariklo's orbit occupies a region of stable chaos, resulting in its orbit being marginally more stable than those of the other Centaurs. Despite this, we find that it was most likely captured to the Centaur population within the last 20 Myr, and that its orbital evolution has been continually punctuated by regular close encounters with the giant planets. The great majority (> 99%) of those encounters within one Hill radius of the planet have only a small effect on the rings. We conclude that close encounters with giant planets have not had a significant effect on the ring structure. Encounters within the Roche limit of the giant planets are rare, making ring creation through tidal disruption unlikely.
On 2017 Mar 10 UT, the 258 km diameter asteroid (10199) Chariklo will occult a 13.0 mag star in the constellation Sagittarius for observers along a path across Australia.
On 2015 May 8th, Centaur (10199) Chariklo will occult a 14.3 mag star in the constellation Sagittarius for observers along a path across the South Pacific