James Webb Telescope just got lucky! All it took, was a star that blinked
Most discoveries have been made with a bit of luck by people who tried very hard. Well, NASA's James Webb Space Telescope too has had some luck as it has discovered water ice in the rings of Chariklo. "By remarkable good luck, we discovered that Chariklo was on track for just such an occultation event in October 2022. This was the first stellar occultation attempted with Webb. A lot of hard work went into identifying and refining the predictions for this unusual event," NASA said in a report.
Notably, in 2013, Felipe Braga-Ribas and others, using ground-based telescopes, discovered that Chariklo hosts a system of two thin rings. Such rings had been expected only around large planets such as Jupiter and Neptune. "The astronomers had been watching a star as Chariklo passed in front of it, blocking the starlight as they had predicted. Astronomers call this phenomenon an occultation. To their surprise, the star blinked off and on again twice before disappearing behind Chariklo, and double-blinked again after the star reemerged. The blinking was caused by two thin rings – the first rings ever detected around a small solar system object," the research organisation explained.
Chariklo is an icy, small body, but the largest of the known Centaur population, located more than 2 billion miles away beyond the orbit of Saturn. Chariklo is only 160 miles (250 kilometers) or ~51 times smaller than Earth in diameter, and its rings orbit at a distance of about 250 miles (400 kilometers) from the center of the body.
On October 18, Webb's Near-Infrared Camera (NIRCam) instrument was used to closely monitor the star Gaia DR3 6873519665992128512, and watch for the tell-tale dips in brightness indicating an occultation had taken place. The
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