NASA’s James Webb Space Telescope (JWST) has made a groundbreaking discovery, revealing that the rings surrounding the asteroid Chariklo are home to water ice. The largest of the known Centaur population, Chariklo is located more than two billion miles beyond Saturn’s orbit.
The rings were first discovered in 2013 using ground-based telescopes, but it was not until the JWST’s recent observations that experts were able to gather more details about the rings. During an occultation, the JWST was able to inspect the asteroid and determine that the rings are likely composed of small particles of water ice mixed with dark debris from an icy body that collided with Chariklo in the past.
The JWST was able to make this discovery due to a remarkable coincidence – Chariklo was on track for an occultation event in October 2022, and the space agency put in a lot of effort to identify and refine the predictions for this rare occurrence. Occultations are the only way to characterise the rings of Chariklo, as the asteroid is too small and too far away for even the JWST to directly image the rings separated from the main body.
NASA’s discovery of water ice in Chariklo’s rings is a major milestone in the field of astronomy and opens up new possibilities for studying our solar system and beyond.