CFCA/NAOJ: New Insights into Chariklo's Ring System

[bystander]

First Global Simulation Yields New Insights into Ring System
Center for Computational Astrophysics | National Astronomical Observatory of Japan | 2017 Apr 28

[img3="Visualization constructed from simulation of Chariklo’s double ring. (Credit:
Shugo Michikoshi, Eiichiro Kokubo, Hirotaka Nakayama, 4D2U Project, NAOJ)"]http://www.cfca.nao.ac.jp/files/michiko ... 05_s_0.png[/img3][hr][/hr]

A team of researchers in Japan modeled the two rings around Chariklo, the smallest body in the Solar System known to have rings. This is the first time an entire ring system has been simulated using realistic sizes for the ring particles while also taking into account collisions and gravitational interactions between the particles. The team’s simulation revealed information about the size and density of the particles in the rings. By considering both the detailed structure and the global picture for the first time, the team found that Chariklo’s inner ring should be unstable without help. It is possible the ring particles are much smaller than predicted or that an undiscovered shepherd satellite around Chariklo is stabilizing the ring.

In order to elucidate the detailed structure and evolution of Chariklo’s rings, Dr. Shugo Michikoshi and Prof. Eiichiro Kokubo performed simulations of the rings by using the supercomputer ATERUI at NAOJ. They calculated the motions of 345 million ring particles with the realistic size of a few meters taking into account the inelastic collisions and mutual gravitational attractions between the particles. Thanks to ATERUI’s many CPUs and the small size of Chariklo’s ring system, the researchers successfully performed the first ever global simulation with realistic sized particles.

Their results show that the density of the ring particles must be less than half the density of Chariklo itself. Their results also showed that a striped pattern, known as “self-gravity wakes,” forms in the inner ring due to interactions between the particles (Figure 2). These self-gravity wakes accelerate the break-up of the ring. The team recalculated the expected lifetime of Chariklo’s rings based on their results and found it to be only 1 to 100 years, much shorter than previous estimates. This is so short that it’s surprising the ring is still there. ...

Simulating the Smallest Ring World of Chariklo - Shugo Michikoshi, Eiichiro Kokubo

• Astrophysical Journal Letters 837(1):L13 (2017 Mar 01) DOI: 10.3847/2041-8213/aa6256
  arXiv.org > astro-ph > arXiv:1702.06356 > 21 Feb 2017