Assessment of different formation scenarios for the ring system of (10199) Chariklo

Context. The discovery that the Centaur (10199) Chariklo possesses a ring system opens questions about their origin. Aims. We here asses the plausibility of different scenarios for the origin of the observed ring system. Methods. We first consider the possibility that the material of the ring originated in the disruption of a satellite that had reached a critical distance from the Centaur. We discuss the conditions for the putative satellite to approach the Centaur as a consequence of tidal interaction. A three-body encounter is also considered as a transport mechanism. In addition, we study the case in which the ring is formed by the ejecta of a cratering collision on the Centaur and we constrain the collision parameters and the size of the resulting crater of the event. Finally, we consider that the ring material originates from a catastrophic collision between a background object and a satellite located at a distance corresponding to the current location of the ring. We compute the typical timescales for these scenarios. Results. We estimate that in order to be tidally disrupted a satellite would have had to be larger than approximately 6.5 km at the location of the rings. However the tidal interaction is rather weak for objects of the size of outer solar system bodies at the ring location, therefore we considered other more effective mechanisms by which a satellite might have approached the Centaur. Collisonal scenarios are both physically plausible for the formation, but semianalytical estimations indicate that the probability of the corresponding collisions is low under current conditions.R.D. acknowledges the support of MINECO for his Ramón y Cajal Contract. Funding from Spanish funding form grant AYA-2014-56637-C2-1-P is acknowledged, as is the Proyecto de Excelencia de la Junta de Andalucía, J. A. 2012-FQM1776. FEDER funds are also acknowledged. R.D. acknowledges the support of MINECO for his Ramon Cajal Contract. Funding from Spanish funding from grant AYA-2014-56637-C2-1-P is acknowledged, as is the Proyecto de Excelencia de la Junta de Andalucía, J. A. 2012- FQM1776. FEDER funds are also acknowledged. M.D.M. acknowledges the support of Min CyT ANPCyt PicT 1144/2013 and the support of the travel grant from CONICET and CSiC