New observations of Jupiter’s Great Red Spot have revealed that the planet’s atmosphere above and around the infamous storm is surprisingly interesting and active. This graphic shows the region observed by Webb—first its location in an NIRCam image of the entire planet (left), and the region itself (right), imaged by Webb’s Near-Infrared Spectrograph (NIRSpec). Credit: ESA/Webb, NASA & CSA, Jupiter ERS Team, J. Schmidt, H. Melin, M. Zamani (ESA/Webb)
Using The James Webb Space Telescopescientists observed the region above Jupiter‘s iconic Great Red Spot to reveal a range of previously unseen features. The region, previously believed to be exceptional in nature, hosts a variety of intricate structures and activities.
Recent observations from Webb’s NIRSpec revealed surprising details about Jupiter’s upper atmosphere, particularly above the Great Red Spot, showing complex structures influenced by gravitational waves. These findings, captured using Webb’s high-resolution capabilities, could support the Jupiter Icy Moons Explorer (Juice) mission, improving our understanding of Jupiter and its moons.
Discovery of Jupiter’s atmosphere
Jupiter is one of the brightest objects in the night sky and is easily seen on a clear night. Apart from the bright northern and southern lights in the planet’s polar regions, the glow from Jupiter’s upper atmosphere is weak and therefore challenging for ground-based telescopes to discern detail in this region. However, Webb’s infrared sensitivity allows scientists to study Jupiter’s upper atmosphere above the infamous Great Red Spot in unprecedented detail.
Jupiter’s upper atmosphere is the interface between the planet’s magnetic field and the underlying atmosphere. Here you can see the bright and vivid displays of the northern and southern lights, which are fueled by volcanic material ejected from Jupiter’s moon Io. Closer to the equator, however, the structure of the planet’s upper atmosphere is affected by incoming sunlight. Because Jupiter receives only 4% of the sunlight received on Earth, astronomers predicted that this region would be homogeneous in nature.
Jupiter’s Great Red Spot was observed by the Webb Near-Infrared Spectrograph (NIRSpec) in July 2022, using the instrument’s integral field unit capabilities. The team’s Early Release Science observations sought to investigate whether this region was in fact faint, and the region above the iconic Great Red Spot was targeted for Webb’s observations. The team was surprised to find that the upper atmosphere hosts a variety of intricate structures, including dark arcs and bright spots, across the entire field of view.
The Webb NIRSpec observations show infrared light emitted by hydrogen molecules in Jupiter’s ionosphere. These molecules extend over 300 km above the storm clouds, where light from the Sun ionizes the hydrogen and stimulates this infrared emission. In this image, the redder colors show hydrogen emission from these high altitudes in the planet’s ionosphere. Blue colors show infrared light from lower altitudes, including cloud tops in the atmosphere and the very prominent Great Red Spot.
Jupiter is far from the Sun and therefore receives a uniform and low level of daylight, meaning that most of the planet’s surface is relatively dim at these infrared wavelengths – especially in comparison with emission from molecules near the poles, where Jupiter’s magnetic field is particularly strong. . Contrary to researchers’ expectations that this area would appear homogeneous in nature, it hosts a variety of complex structures, including dark arcs and bright spots, across the field of view.
Credit: ESA/Webb, NASA & CSA, H. Melin, M. Zamani (ESA/Webb)
Surprising findings on the Great Red Spot
“We thought this region, perhaps naively, would be really boring,” said team leader Henrik Melin of the University of Leicester in the United Kingdom. “It’s actually just as interesting as the northern lights, if not more so. Jupiter never ceases to amaze.”
Although the light emitted from this region is driven by sunlight, the team suggests there must be another mechanism that changes the shape and structure of the upper atmosphere.
“One way you can change this structure is by gravity waves – similar to waves crashing on a beach, creating ripples in the sand,” Henrik explained. “These waves are created deep in the turbulent lower atmosphere around the Great Red Spot, and they can travel up in altitude, changing the structure and emissions of the upper atmosphere.”
Future observations and implications
The team explains that these atmospheric waves can be observed on Earth on occasion, however, they are much weaker than those observed on Jupiter by Webb. They also hope to conduct follow-up Webb observations of these complex wave patterns in the future to investigate how the patterns move within the planet’s upper atmosphere and develop our understanding of this region’s energy budget and that how traits change over time.
These findings may also support ESA’s Jupiter Icy Moons explorer, Juice, which was launched on April 14, 2023. Juice will make detailed observations of Jupiter and its three large ocean-bearing moons – Ganymede, Callisto and europe – with a suite of remote, geophysical and in situ sensing instruments. The mission will characterize these moons as planetary objects and potential habitats, explore Jupiter’s complex environment in depth, and study the wider Jupiter system as an archetype for gas giants throughout the Universe.
Reflections on the impact of research
These observations were obtained as part of the Early Release Science program #1373: ERS observations of the Jovian system as a demonstration of JWST’s solar system science capabilities (Co-PIs: I. de Pater, T. Fouchet).
“This ERS proposal was written in 2017,” said team member Imke de Pater of University of California, Berkeley. “One of our objectives had been to investigate why the temperature above the Great Red Spot appeared to be high, since at the time of the last observations with NASA The infrared telescope unit had detected. However, our new data showed very different results.”
These results are published in Astronomy of Nature.
Reference: “Ionospheric irregularities in Jupiter observed by JWST” by Henrik Melin, J. O’Donoghue, L. Moore, TS Stallard, LN Fletcher, MT Roman, J. Harkett, ORT King, EM Thomas, R. Wang, PI Tiranti , KL Knowles, I. de Pater, T. Fouchet, PH Fry, MH Wong, BJ Holler, R. Hueso, MK James, GS Orton, A. Mura, A. Sánchez-Lavega, E. Lellouch, K. de Kleer and MR Showalter, June 21, 2024, Astronomy of Nature.
DOI: 10.1038/s41550-024-02305-9
Webb is the largest and most powerful telescope ever launched into space. Under an international cooperation agreement, ESA provided the launch service for the telescope, using the Ariane 5 launch vehicle. Working with partners, ESA was responsible for the development and qualification of Ariane 5 adaptations for the Webb mission and for the procurement of the launch service from Arianespace . ESA also provided the working NIRSpec spectrograph and 50% of the mid-infrared instrument bestwhich was designed and built by a consortium of nationally funded European Institutes (MIRI European Consortium) in partnership with JPL and the University of Arizona.
Webb is an international partnership between NASA, ESA and the Canadian Space Agency (CSA).