James Webb Space Telescope Discovery

Enceladus Plume

Images from the NASA/ESA/CSA James Webb Space Telescope’s NIRCam (Near-Infrared Camera) show a water vapour plume jetting from the south pole of Saturn’s moon Enceladus, extending out 40 times the size of the moon itself. The inset, an image from the Cassini orbiter, emphasises how small Enceladus appears in the Webb image compared to the water plume. Webb is allowing researchers, for the first time, to see directly how this plume feeds the water supply for the entire system of Saturn and its rings. By analysing the Webb data, astronomers have determined roughly 30 percent of the water stays within a torus, a fuzzy doughnut of water that is co-located with Saturn’s E-ring, and the other 70 percent escapes to supply the rest of the Saturnian system with water. Enceladus, an ocean world about four percent the size of Earth at just 505 kilometres across, is one of the most exciting scientific targets in our Solar System in the search for life beyond Earth. A global reservoir of salty water sits below the moon’s icy outer crust, and geyser-like volcanoes spew jets of ice particles, water vapour, and organic chemicals out of crevices in the moon’s surface informally called ‘tiger stripes’. Webb’s NIRCam was built by a team at the University of Arizona and Lockheed Martin’s Advanced Technology Center. Credit: NASA, ESA, CSA, STScI, G. Villanueva (NASA’s Goddard Space Flight Center), A. Pagan (STScI) Enceladus (NIRCam Image) NASA’s James Webb Space Telescope’s exquisite sensitivity and highly specialised instruments are revealing details into how one of Saturn’s moon’s feeds the water supply for the entire system of the ringed planet. Enceladus, a prime candidate in the search for life elsewhere in our Solar System, is a small moon about four percent the size of Earth. New images from Webb’s NIRCam (Near-Infrared Camera) have revealed a water vapour plume jetting from the south pole of Enceladus, extending out 40 times the size of the moon itself. The Integral Field Unit (IFU) aboard the NIRSpec (Near-Infrared Spectrograph) instrument also provided insights into how the water from Enceladus feeds the rest of its surrounding environment. Enceladus orbits around Saturn in just 33 hours, and as it does it sprays water and leaves behind a torus — or ‘doughnut’ — of material in its wake. This torus is depicted in the top diagram in light blue. Webb’s IFU is a combination of camera and spectrograph. During an IFU observation, the instrument captures an image of the field of view along with individual spectra of each pixel in the field of view. IFU observations allow astronomers to investigate how properties — composition in this case — vary from place to place over a region of space. The unique sensitivity of Webb’s IFU allowed researchers to detect many spectral features characteristic of water originating from the embedding torus around Enceladus and the plume itself. This simultaneous collection of spectra from the plume and the torus has allowed researchers to better understand their strong relationship. In this spectrum, the white lines are the data from Webb, and the best-fit models for water emission are overlaid in different colours –purple for the plume, green for the area central to the moon itself, and red for the surrounding torus. Credit: NASA, ESA, CSA, STScI, L. Hustak (STScI), G. Villanueva (NASA’s Goddard Space Flight Center) Enceladus (NIRCam and NIRSpec IFU)
Raw images
Images from the original article (unofficial)

Credit: Kelly Lepo, STScI