NASA’s James Webb Space Telescope has discovered a new, never-before-seen feature in Jupiter’s atmosphere. The high-speed jet stream, which spans more than 4,800 kilometers wide, is located above Jupiter’s equator, above the major cloud layers.. There are winds of 515 kilometers per hour there.
The discovery of this jet offers insights into how the layers of Jupiter’s famously turbulent atmosphere interact with each other and how the Webb space telescope is the only one capable of tracking those features.
“It is something that totally surprised us,” acknowledges Ricardo Hueso, from the University of the Basque Country (Spain), main author of the study that is being published. Nature Astronomy in which they describe the findings.
“What we have always seen as blurry haze in Jupiter’s atmosphere now appear as sharp features that we can track along with the planet’s rapid rotation,” says Hueso.
The team of scientists analyzed data from Webb’s NIRCam (near-infrared camera) captured in July 2022. The program Early Release Scienceco-led by Imke de Pater of the University of California at Berkeley and Thierry Fouchet of the Paris Observatory, was designed to image Jupiter 10 hours apart, or one Jupiter day, in four different filters, each one of them.
Imke de Pater explains that, “although several ground-based telescopes, spacecraft such as NASA’s Juno and Cassini, and the Hubble Space Telescope have observed the changing weather patterns of the Jovian system, Webb has already provided new findings about Jupiter’s rings, satellites and atmosphere”.
Jupiter’s atmosphere
While Jupiter is different from Earth in many ways (it is a gas giant and Earth is rocky and temperate), both planets have layered atmospheres. The infrared, visible, radio and ultraviolet light wavelengths observed by these other missions detect the lower, deeper layers of the planet’s atmosphere, where giant storms and clouds of ammonia ice reside.
On the other hand, the Webb telescope’s near-infrared gaze is more sensitive to the higher altitude layers of the atmosphere, about 25 to 50 kilometers above Jupiter’s cloud tops. In near-infrared images, high-altitude haze often appears blurry, with brighter light in the equatorial region. With Webb, the finer details are resolved within the bright, hazy band.
In this work, it is said that Newly discovered jet stream travels at approximately 515 kilometers per hour, twice the sustained winds of a Category 5 hurricane on Earth. It is located about 40 kilometers above the clouds, in Jupiter’s lower stratosphere.
By comparing the winds observed by Webb at high altitude with those from deeper layers from Hubble, this team was able to measure how quickly the winds change with altitude.
They point out that while Webb’s exquisite resolution and wavelength coverage allowed the detection of small cloud features used to track the jet, complementary Hubble observations, taken a day after Webb’s, were also crucial in determining the base state of Jupiter’s equatorial atmosphere and observe the development of convective storms at the equator not connected to the jet.
Complicated wind pattern
In this sense, Michael Wong of the University of California at Berkeley, who led the associated Hubble observations, emphasizes that “we knew that the different wavelengths of Webb and Hubble would reveal the three-dimensional structure of storm clouds, but We were also able to use data timing to see how quickly storms develop”.
Researchers await additional observations of Jupiter with the Webb telescope to determine whether the speed and altitude of the jet they change over time.
In this order of things, Leigh Fletcher, a planetary scientist at the University of Leicester, in the United Kingdom, points out that “Jupiter has a complicated but repeatable pattern of winds and temperatures in its equatorial stratosphere, well above the cloud winds and hazes measured at these wavelengths. “If the strength of this new jet is related to this oscillating stratospheric pattern, we could expect the jet to vary considerably over the next two to four years.”
