Space scientists reveal secret of Jupiter’s “energy crisis”

New research published in Nature revealed the solution to Jupiter’s “energy crisis”, which has puzzled astronomers for decades.

Space scientists from the University of Leicester worked with colleagues from the Japan Space Agency (JAXA), Boston University, NASA’s Goddard Space Flight Center, and the National Institute of Information and Communications Technology (NICT) to reveal the mechanism behind Jupiter’s atmospheric warming.

Now, using data from the Keck Observatory in Hawai’i, astronomers have created the most detailed yet comprehensive map of the gas giant’s upper atmosphere, confirming for the first time that Jupiter’s powerful auroras are responsible for the global heating.

Dr James O’Donoghue is a research fellow at JAXA and has completed his doctorate. in Leicester, and is the lead author of the research paper. He said:

“We first started trying to create a global heat map of Jupiter’s upper atmosphere at the University of Leicester. The signal was not bright enough to reveal anything outside of Jupiter’s polar regions. back then, but with the lessons learned from that work, we were able to save time on one of the largest and most competitive telescopes on Earth a few years later.

“Using the Keck telescope, we produced temperature maps of extraordinary precision. We found that temperatures start very high in the aurora, as predicted in previous work, but we can now observe that the aurora of Jupiter, although it occupies less than 10% of the surface of the planet, seem to heat everything.

“This research began in Leicester and continued at Boston University and NASA before ending at JAXA in Japan. Collaborators from every continent working together made this study successful, combined with data from the spacecraft. NASA’s Juno spacecraft orbiting Jupiter and JAXA’s Hisaki spacecraft, an observatory in space. “

Dr Tom Stallard and Dr Henrik Melin are both part of the School of Physics and Astronomy at the University of Leicester. Dr Stallard added:

“There is a long-standing puzzle in the thin atmosphere atop every giant planet in our solar system. With every space mission from Jupiter, as well as observations on the ground, over the past 50 years, we have consistently measured the equatorial temperatures as being much too hot.

“This ‘energy crisis’ has been a long-standing problem – do models fail to correctly model how heat flows from aurora, or is there another unknown heat source near the equator?

“This article describes how we mapped this region in unprecedented detail and showed that in Jupiter, equatorial heating is directly associated with auroral heating.”

Auroras occur when charged particles are captured in a planet’s magnetic field. These spiral along field lines toward the planet’s magnetic poles, striking atoms and molecules in the atmosphere to release light and energy.

On Earth, this leads to the characteristic light show that forms the Northern Lights and Austral. In Jupiter, the spitting material from its volcanic moon, Io, leads to the most powerful aurora in the solar system and huge warming in the polar regions of the planet.

Although the Jovian Aurora has long been a prime candidate for heating the planet’s atmosphere, observations so far have not been able to confirm or deny it.

Previous maps of upper atmospheric temperature were formed using images consisting of only a few pixels. This is not sufficient resolution to see how the temperature might change across the planet, providing little clue as to where the extra heat is coming from.

The researchers created five maps of the atmospheric temperature at different spatial resolutions.

The team traversed over 10,000 individual data points, mapping only points with less than five percent uncertainty.

The gas giant’s atmospheric models suggest that they function like a giant refrigerator, with thermal energy drawn from the equator to the pole, and deposited in the lower atmosphere in these polar regions.

These new findings suggest that the shifting auroras can wave energy against this flux towards the poles, allowing heat to reach the equator.

The observations also showed a region of localized heating in the subauroral region which could be interpreted as a limited wave of heat propagating towards the equator, which could be interpreted as evidence of the process causing heat transfer.

Planetary research at the University of Leicester covers the extent of the Jovian system, magnetosphere and atmosphere of the planet to its diverse collection of satellites.