The Structure of Chariklo’s Rings from Stellar Occultations

Abstract

Two narrow and dense rings (called C1R and C2R) were discovered around the Centaur object (10199) Chariklo during a stellar occultation observed on 2013 June 3. Following this discovery, we planned observations of several occultations by Chariklo's system in order to better characterize the physical properties of the ring and main body. Here, we use 12 successful occulations by Chariklo observed between 2014 and 2016. They provide ring profiles (physical width, opacity, edge structure) and constraints on the 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. The six resolved C1R profiles reveal significant width variations from ∼5 to 7.5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 1s 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.

Characterization of material around the centaur (2060) Chiron from a visible and near-infrared stellar occultation in 2011

“…Unlike Chariklo's relatively azimuthally-congruent, more substantial inner ring (τ N~ 0.4) and more optically thin outer ring (τ N~ 0.06), the proposed rings at Chiron are like each other. Chiron's A1-A4 match Chariklo's inner ring in equivalent depth and the A1 & A4 and A2 & A3 radial widths vary by similar amounts at different azimuths, similar to the variations reported for Chariklo's inner ring (Bérard et al 2017). The detection limits (>4σ) on this dataset are τ N~ 0.05 for 20-km features and τ N~ 0.18 for 2-km features; therefore, a feature like Chariklo's outer ring would not have been detected.…”

“…In 2013, a ring system around the centaur (10199) Chariklo was detected via a stellar occultation observation (Braga-Ribas et al 2014). This system is remarkably similar to the features observed at Chiron: Chariklo is 248±18 km in size (Fornasier et al 2013) and the rings are located 391 and 405 km from the centre of the nucleus, with widths of roughly 7 and 3 km, respectively (Bérard et al 2017, Braga-Ribas et al 2014. Ortiz et al (2015) combined the results from Ruprecht et al (2015) with new rotational light curves and long-term brightness and spectroscopic variations to propose that Chiron has a full ring system similar to Chariklo's.…”

Dynamics around Non-Spherical Symmetric Bodies: I. The case of a spherical body with mass anomaly

“…In this section, we briefly study the dynamics around Chariklo, in particular in the region of the ring. The rings have orbital radii of 391 km and 405 km, with radial widths of 7 km and 3 km, respectively (Bérard et al 2017).…”

“…10199 Chariklo is another irregular body with a complex system involving a pair of narrow rings and possibly small satellites (Braga-Ribas et al 2014;Bérard et al 2017). The shape of Chariklo is still not well known.…”

A stellar occultation by Vanth, a satellite of (90482) Orcus

“…The idea that rings or other coma material could exist in the Orcus system is based on recent discoveries of a ring around the dwarf planet Haumea , a pair of rings around the centaur Chariklo (Bérard et al, 2017;Braga-Ribas et al, 2014), and possibly jets, a shell of material, or rings around the centaur Chiron (Bus et al, 1996;Elliot et al, 1995;Ortiz et al, 2015;Ruprecht et al, 2015). The centaur rings are 3-7 km in width and Haumea's ring is roughly 70-km wide.…”