Global upper-atmospheric heating on Jupiter by the polar aurorae

Area of Science:

• Planetary Science
• Atmospheric Physics
• Space Physics

Background:

• Jupiter's upper atmosphere is unexpectedly hot, with auroral energy deposition concentrated at polar regions.
• Global circulation models suggest auroral energy is trapped at high latitudes, prompting study of alternative heat sources like gravity and acoustic waves.
• Previous studies lacked planet-wide, high-resolution data to determine Jovian temperature gradients and dominant heat sources.

Purpose of the Study:

• To investigate Jupiter's global temperature gradients in the upper atmosphere.
• To identify the primary heat source responsible for Jupiter's atmospheric temperature distribution.
• To test the hypothesis of auroral energy redistribution versus lower-atmosphere wave heating.

Main Methods:

• Infrared spectroscopy of Jupiter was performed with high spatial resolution (2 degrees latitude and longitude).
• Observations covered the entire planet from pole to equator.
• Data analysis focused on mapping temperature gradients and identifying large-scale thermal structures.

Main Results:

• Temperatures were found to decrease steadily from the auroral polar regions towards the equator.
• A high-temperature, planetary-scale structure was observed during a period of enhanced solar wind activity, potentially propagating from the aurora.
• These findings challenge previous models and suggest a link between auroral activity and global atmospheric temperatures.

Conclusions:

• Jupiter's upper atmosphere is predominantly heated by the redistribution of energy from auroral processes.
• Auroral energy is not entirely trapped at high latitudes but influences temperatures across the planet.
• This study provides crucial observational evidence for the dominant energy transfer mechanism in Jupiter's atmosphere.