New observations with the Subaru Telescope, a Japanese 8-m telescope on Mauna Kea, Hawaii, show that aurorae at Jupiter’s poles are heating the atmosphere of the gas giant to a greater depth than previously thought — and that it is a rapid response to the solar wind.
This infrared image was recorded by Subaru Telescope’s COMICS instrument. Sinclair et al used red, blue and yellow to infuse this image; regions of the atmosphere that are more yellow and red indicate the hotter areas. This highlights the auroral heating that occurs at Jupiter’s poles, where energy from the solar wind and magnetosphere are deposited. This image was captured on January 12, 2017. Image credit: NAOJ / NASA / JPL-Caltech.
Aurorae at Earth’s poles occur when the energetic particles blown out from the Sun — the solar wind — interact with and heat up the gases in the upper atmosphere.
The same thing happens at Jupiter, but the new observations show the heating goes 2-3 times deeper down into its atmosphere than on Earth, into the lower level of Jupiter’s stratosphere (upper atmosphere).
Understanding how the Sun’s constant outpouring of solar wind interacts with planetary environments is key to better understanding the very nature of how planets and their atmospheres evolve.
“The solar wind impact at Jupiter is an extreme example of space weather,” said Dr. James Sinclair, a researcher at NASA’s Jet Propulsion Laboratory.
“We’re seeing the solar wind having an effect deeper than is normally seen.”
Dr. Sinclair and colleagues analyzed images from the Cooled Mid-Infrared Camera and Spectograph (COMICS) on the Subaru Telescope.
“What is startling about the results is that we were able to associate for the first time the variations in solar wind and the response in the stratosphere — and that the response to these variations is so quick for such a large area,” said Dr. Glenn Orton, also from NASA’s Jet Propulsion Laboratory.
Within a day of the solar wind hitting Jupiter, the chemistry in its atmosphere changed and its temperature rose, the astronomers found.
“Such heating and chemical reactions may tell us something about other planets with harsh environments, and even early Earth,” said Dr. Yasumasa Kasaba, from Tohoku University.
The results appear in the journal Nature Astronomy.
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J.A. Sinclair et al. A brightening of Jupiter’s auroral 7.8-μm CH4 emission during a solar-wind compression. Nature Astronomy, published online April 8, 2019; doi: 10.1038/s41550-019-0743-x
