Multiring basin formation constrains Europa's ice shell thickness.

Area of Science:

• Planetary Science
• Geophysics
• Astrobiology

Background:

• Jupiter's moon Europa is known to possess a subsurface ocean beneath an icy crust.
• Europa features two prominent multiring basins, whose formation is influenced by the ice shell's properties.
• Understanding the ice shell's thickness and thermal structure is crucial for assessing Europa's habitability.

Purpose of the Study:

• To investigate the relationship between impact-induced multiring basin formation and Europa's ice shell structure.
• To determine the minimum ice shell thickness required to replicate observed ring structures on Europa.
• To constrain the thermal profile of Europa's ice shell.

Main Methods:

• Numerical simulations of impact events on Europa's ice shell.
• Modeling of multiring basin formation dynamics.
• Analysis of ring structures resulting from varying ice shell thicknesses and thermal conditions.

Main Results:

• Simulations indicate a minimum ice shell thickness exceeding 20 kilometers is necessary to form observed multiring structures.
• Ice shells thinner than 15 kilometers produce compressional tectonics, inconsistent with Europa's surface features.
• The ice shell is likely composed of a 6- to 8-kilometer conductive lid over a convecting ice layer.

Conclusions:

• Europa's ice shell thickness is constrained to be greater than 20 km, with a specific layered thermal structure.
• These findings have significant implications for the potential habitability of Europa's subsurface ocean.
• The study provides a framework for future research on icy moon geophysics and astrobiology.