Jupiter’s atmosphere contains an unexpected “heat wave” that is 700 degrees Celsius and spans 130,000 kilometres (10 Earth diameters). The findings were presented this week at the Europlanet Science Congress (EPSC) 2022 in Granada by James O’Donoghue of the Japanese Aerospace Exploration Agency (JAXA).
Jupiter’s atmosphere, noted for its distinctive multicoloured vortices, is also unusually hot: hundreds of degrees hotter than theories predict. Due to its orbital distance of millions of kilometres from the Sun, the giant planet receives less than 4% as much sunlight as Earth, and its upper atmosphere should potentially be -70 degrees Celsius. Instead, temperatures in its upper atmosphere consistently exceed 400 degrees Celsius.
“Last year we produced – and presented at EPSC2021,” says Dr. O’Donoghue, “the first maps of Jupiter’s upper atmosphere capable of identifying the dominant heat sources.”
With the help of these maps, they showed “that Jupiter’s auroras were a possible mechanism that could explain these temperatures.”
Jupiter, like Earth, has auroras around its polar regions as a result of the solar wind. However, Jupiter’s auroras are permanent and vary in strength, in contrast to Earth’s auroras, which are fleeting and only manifest when solar activity is high. Strong auroras have been known to heat the area near the poles to over 700 degrees Celsius, while global winds have been known to transport heat across the entire area around Jupiter.
Dr. O’Donoghue and his team uncovered the stunning “heat wave” right beneath the northern aurora by digging further into their data, and they discovered that it was moving towards the equator at a speed of thousands of kilometres per hour.
The amplified solar wind plasma pulse that struck Jupiter’s magnetic field and increased auroral heating likely caused the heat wave by forcing heated gases to expand and spill out towards the equator.
“While the auroras continuously deliver heat to the rest of the planet, these heat wave ‘events’,” as explained by Dr. O’Donoghue, “represent an additional, significant energy source.”
The find adds “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.”
Image Credit: Hubble / NASA / ESA / A. Simon (NASA GSFC) / J. Schmidt. Credit: James O’Donoghue