The high-temperature planetary-scale-sized structure is at least 130,000 km (80,778 miles) long, according to a new study led by JAXA scientists.
The atmosphere of Jupiter, famous for its characteristic multicolored vortices, is also unexpectedly hot: in fact, it is hundreds of degrees hotter than models predict.
Due to its orbital distance millions of kilometers from the Sun, the giant planet receives under 4% of the amount of sunlight compared to Earth, and its upper atmosphere should theoretically be minus 70 degrees Celsius (minus 94 degrees Fahrenheit).
Instead, its cloud tops are measured everywhere at over 400 degrees Celsius (752 degrees Fahrenheit).
“Last year we produced the first maps of Jupiter’s upper atmosphere capable of identifying the dominant heat sources,” said JAXA researcher Dr. James O’Donoghue.
“Thanks to these maps, we demonstrated that Jupiter’s aurorae were a possible mechanism that could explain these temperatures.”
Just like the Earth, Jupiter experiences aurorae around its poles as an effect of the solar wind.
However, while Earth’s aurorae are transient and only occur when solar activity is intense, aurorae at Jupiter are permanent and have a variable intensity.
The powerful aurorae can heat the region around the poles to over 700 degrees Celsius, and global winds can redistribute the heat globally around Jupiter.
Looking more deeply through their data, Dr. O’Donoghue and his colleagues discovered the spectacular ‘heat wave’ just below the northern aurora, and found that it was traveling towards the equator at a speed of thousands of kilometers per hour.
The heat wave was probably triggered by a pulse of enhanced solar wind plasma impacting Jupiter’s magnetic field, which boosted auroral heating and forced hot gases to expand and spill out towards the equator.
“While the aurorae continuously deliver heat to the rest of the planet, these heat wave ‘events’ represent an additional, significant energy source,” Dr. O’Donoghue said.
“These findings add to our knowledge of Jupiter’s upper-atmospheric weather and climate, and are a great help in trying to solve the ‘energy crisis’ problem that plagues research into the giant planets.”
Dr. O’Donoghue and co-authors presented the findings this week at the Europlanet Science Congress (EPSC) 2022 in Granada, Spain.
J. O’Donoghue et al. A planetary-scale heat wave in Jupiter’s mid-latitude upper atmosphere. EPSC Abstracts 16; EPSC2022-373; doi: 10.5194/epsc2022-373
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