New observations from Earth-based telescopes show that auroras at Jupiter's poles are heating the planet's atmosphere to a greater depth than previously thought. – And that is a quick response to the solar wind.
"The impact of the solar wind on Jupiter is an extreme example of space weather," said James Sinclair of NASA's Jet Propulsion Laboratory in Pasadena, Calif., Who led new research published on April 8 in Nature Astronomy. "We are seeing that the solar wind has a deeper effect than is normally seen."
The auroras at the Earth's poles (known as the aurora borealis at the North Pole and the southern aurora at the South Pole) occur when the energetic particles ejected from the Sun (the solar wind) interact and heat the gases in the upper atmosphere. The same thing happens in Jupiter, but the new observations show that the warming goes two or three times deeper in its atmosphere than on Earth, in the lower level of Jupiter's upper atmosphere, or stratosphere.
Understanding how the constant flow of sunlight from the solar wind interacts with planetary environments is key to better understanding the very nature of how planets and their atmospheres evolve.
"The surprising thing about the results is that we were able to badociate for the first time the variations in the solar wind and the response in the stratosphere, and that the response to these variations is so fast for such a large area," said Glenn from JPL. Orton, co-author and part of the observation team.
A day after the solar wind hit Jupiter, the chemistry in its atmosphere changed and its temperature increased, the team found. An infrared image captured during its observation campaign in January, February and May 2017 clearly shows the hot spots near the poles, where the auroras of Jupiter are located. The scientists based their findings on observations made by the Subaru Telescope, at the top of the Mauna Kea summit in Hawaii, operated by the National Astronomical Observatory of Japan.
The telescope's cooled camera and mid-infrared spectrograph (COMICS) recorded thermal images, capturing areas of higher or lower temperatures, of Jupiter's stratosphere.
"Such chemical and warming reactions can tell us something about other planets with hostile environments and even primitive Earth," said Yasumasa Kasaba of Tohoku University, who also worked on the observation team.
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Jet Propulsion Laboratory, Pasadena, California.