Using the James Webb Space Telescope (JWST), astronomers have revealed new insights into the ring system of Chariklo, a small solar system object located between Saturn and Uranus. This body, approximately 155 miles (250 kilometers) wide, is part of the Centaur family of asteroids and hosts two thick rings.
While Saturn is renowned for its rings, other planets like Uranus, Neptune, and Jupiter also possess ring systems, albeit less prominent. Chariklo and another body, Chiron, demonstrate that even smaller celestial bodies can have rings. Initial discoveries in 2013 were expanded upon through JWST observations, which indicated that Chariklo’s rings are more enigmatic than previously understood.
The research team from the Institute of Astrophysics of Andalusia began their JWST observations in October 2022 using a method called stellar occultation, measuring starlight dimming as Chariklo passed in front of a star. They found contrasting changes in the two rings: the inner ring significantly increased in opacity, while the outer ring’s opacity decreased. This disparity suggests more complex physical processes at play than previously thought, challenging the belief that rings around small bodies are relatively stable.
Team leader Pablo Santos-Sanz emphasized that these findings prompt a reevaluation of the formation, evolution, and stability mechanisms of such ring systems, potentially reshaping our understanding of other solar system rings.
The cause of these changes remains unknown, but the study represents a significant milestone for JWST, showcasing its capability in studying asteroids and their rings. The precise orbital knowledge of Chariklo, along with data from the European Space Agency’s Gaia mission, was crucial for this study.
The team’s findings have been published in Science Advances, illustrating the ongoing challenges in directly imaging distant small bodies like Chariklo, relying instead on techniques like occultation for detailed analysis.
