Jupiter is a complex system full of mysteries, hosting spheres of questions about the nature of its delicate rings, how its largest moons harbor oceans of water or hidden volcanoes, and how massive storms like the Great Red Spot form in the giant planet’s turbulent atmosphere. . The planet will be the perfect “proving ground,” researchers say, for the James Webb Space Telescope, the $10 billion observatory that will show its first operational images on July 12. “It’s going to be a really challenging experiment,” study co-leader Imke de Pater, a planetary scientist at the University of California, said of Webb’s upcoming studies of Jupiter in a 2020 consortium statement (opens in new tab). “Jupiter is so bright and Webb’s instruments are so sensitive that observing both the bright planet and its fainter rings and moons will be an excellent test of how to get the most out of Webb.” added de Pater, who leads. the study with Thierry Fouchet of the Observatoire de Paris. Jupiter is a bright target that will require precise calibrations of Webb’s instruments so that the planet doesn’t wash out in the telescope’s sensitive optics. The gas giant is also spinning rapidly, making it more difficult to capture a time-lapse image to perform scientific observations. But once those hurdles are overcome, scientists say they look forward to new ideas using Webb’s unique 18-segment mirror and four infrared instruments. Atmospheric studies of Jupiter will feature prominently. For example, the telescope will study the enigmatic polar storms, also monitored by NASA’s Juno spacecraft, to examine their winds, clouds, gas and temperature. Webb will also examine the atmosphere just above the swirling Great Red Spot, which has unexplained temperature variations (for example, the atmosphere just above is much colder than other zones of Jupiter.) Further afield, the team hopes to spot new moons in Jupiter’s rings. That will be especially difficult as the planet’s bright light can wash out the faint ring system made up of tiny and sparse dust particles, officials said. (Strategies to deal with this problem can help future exoplanet observers who use Webb to see faint worlds next to bright stars.)
Falcons surround Jupiter’s north pole in this infrared image from NASA’s Juno spacecraft. (Image credit: NASA, Caltech, SwRI, ASI, INAF, JIRAM) Then there are the large moons of Jupiter. This first set of studies will look at icy Ganymede and volcanic Io to gain more insight into how these worlds formed and changed over time. Ganymede’s outer atmosphere will be imaged by Webb to “better understand the moon’s interaction with particles in Jupiter’s magnetic field,” the researchers said. Webb will also search for a suspected saltwater ocean beneath Ganymede’s surface. The Io surveys will include a search for “stealth volcanoes,” which researchers suspect erupt without scattering dust particles that would better reflect light for telescopes to see. Webb, however, has a higher spatial resolution than previous missions to Jupiter (including Voyager and Galileo), allowing it to spot potentially hidden volcanoes along with “hotspots.” The high temperature concentrations on Io’s surface may be similar to those seen with volcanic Earth, but more study is needed to confirm Galileo’s observations in the 1990s and 2000s. The telescope will also look in detail at the temperature structure of Io, which so far is relatively unknown as not much data has been collected about the temperature at different heights of the moon’s atmosphere, the statement said.
NASA’s Galileo spacecraft caught Jupiter’s moon Io, the planet’s third largest moon, undergoing a volcanic eruption. (Image credit: NASA/JPL/DLR) As Webb turns its sights on Jupiter from deep space, observatories orbiting closer to the planet will provide assistance. For example, Webb’s distant view of Jupiter’s atmosphere will provide valuable context for Juno orbiting Jupiter. “No one observatory or spacecraft can do it all,” study co-investigator Michael Wong of the University of California, Berkeley, said in the same statement. “We are very excited to combine data from multiple observatories to tell us much more than we could learn from a single source.” Follow Elizabeth Howell on Twitter @howellspace (opens in new tab). Follow us on Twitter @Spacedotcom (opens in new tab) and Facebook (opens in new tab).
