A team of astronomers suggests that a unidentified moon might be influencing the rings of Chariklo, a small object that orbits the Sun between Saturn and Uranus. Chariklo, which is approximately 160 miles (257.5 kilometers) in diameter, is the largest of the Centaurs, a collection of icy bodies located between Jupiter and Uranus. The small planet also possesses two rings, which were discovered in 2013 and recently observed using the Webb Space Telescope.A recent study published in The Planetary Science Journal indicates that a moon may be constraining Chariklo’s narrow rings. According to Amanda Sickafoose, a researcher at the Planetary Science Institute and the lead author of the study, “Planetary rings will naturally spread or disperse over time. Chariklo exhibits two thin rings, a few kilometers in width. In order for the rings to remain this thin, there needs to be a mechanism to confine the material and prevent it from dispersing.”The researchers utilized N-body simulations to model how a moon could sustain Chariklo’s rings. They determined that a moon orbiting Chariklo could have a diameter of about 3.73 miles (6 km). This supports the idea that a shepherd moon could confine Chariklo’s rings, as previously suggested. The team also found that the rings are located near, or even beyond, the Roche limit, the minimum distance from a celestial body at which rings can form. Beyond this limit, ring material would be gravitationally drawn into the moon.”There has been significant research into the dazzling rings around the giant planets; however, the mechanisms of ring formation and evolution around small objects are not well understood,” Sickafoose stated. “We’ve shown that one of the possibilities for thin rings to exist around small bodies is that they are being sculpted by a small satellite.”Further observations may help confirm whether a moon is orbiting around Chariklo, although current imaging technology lacks the capability to directly detect it. Resolving the mystery will likely require indirect observations or a new mission.
