Complex structure within Saturn's infrared aurora.

Area of Science:

• Planetary Science
• Space Physics
• Astrophysics

Background:

• Planetary aurorae are typically generated by electrical currents between the ionosphere and magnetosphere, accelerating charged particles.
• At Saturn, these interactions cause ultraviolet and infrared emissions through hydrogen excitation and ionization.
• The precise source of these auroral currents remains debated, with models predicting limited emission outside the main auroral oval.

Purpose of the Study:

• To investigate the source and morphology of auroral emissions at Saturn beyond the main auroral oval.
• To analyze the relationship between solar wind conditions and observed auroral patterns.
• To understand the underlying magnetospheric processes responsible for unique auroral features.

Main Methods:

• Analysis of newly acquired images showing auroral emissions at Saturn.
• Correlation of auroral morphology with solar wind dynamic pressure variations.
• Comparison of observed emissions with existing magnetospheric models.

Main Results:

• Discovery of significant auroral emissions poleward and equatorward of the main auroral oval.
• The polar emissions exhibit high temporal variability and disappear during spiral auroral events.
• Equatorward auroral arcs are observed exclusively on Saturn's nightside.

Conclusions:

• The polar auroral emissions are likely linked to minor solar wind pressure changes but not strong magnetospheric compressions.
• These polar emissions appear unique to Saturn and challenge current magnetospheric understanding.
• The nightside equatorward auroral arcs originate from currently unknown internal magnetospheric processes.