An occultation light curve from Webb’s Near-infrared Camera (NIRCam) Instrument at 1.5 microns wavelength (F150W) shows the dips in brightness of the star (Gaia DR3 6873519665992128512) as Chariklo’s rings passed in front of it on October 18, 2022. As seen in the illustration of the occultation event, the star did not pass behind Chariklo from Webb’s viewpoint, but it did pass behind its rings. Each dip actually corresponds to the shadows of two rings around Chariklo, which are 6-7 km and 2-4 km wide, and separated by a gap of 9 km, that are not fully resolved in this light curve.
webb logo

01/25/2023 : Webb scientists use high-precision occultation technique to spy Chariklo ring system

In an observational feat of remarkably high precision, scientists used a new technique with NASA’s James Webb Space Telescope to capture the shadows of starlight cast by the thin rings of Chariklo. Chariklo is a small object, but the largest of the known Centaur population, located more than 2 billion miles away beyond the orbit of Saturn. Chariklo is only 250 kilometers (160 miles, or ~51 times smaller than Earth) in diameter and its rings orbit at a distance of about 400 kilometers (250 miles) from the center of the body.

Webb Images : About | 2023 | 2022 | 1st Images | In Depth