Description
Jupiter’s moon Io is tidally locked with Jupiter and falls in a 4:2:1 orbital
resonance with Europa and Ganymede, driving extreme tidal heating that makes it the most volcanically active body in the solar system. Io possesses a metallic core, as does its Galilean sibling Ganymede, yet, unlike Ganymede, Io lacks a magnetic field. Here, I investigated the potential size, composition, and cooling rate of Io’s core to help determine why Io lacks a strong dynamo. First, I used mineral physics equations to determine that the radius of the core should be between ~650 km to 950 km for a composition ranging from pure Fe to a eutectic Fe-FeS alloy. Cosmochemical constraints from meteoritic analogues yield complementary constraints on the abundance of sulfur in the metallic core (~2.67–28.6 wt%). The mantle could be either fully or partially molten. I found that the scenario of a global magma ocean creates temperatures at the base of the mantle that are possibly too hot for core convection, but that a magma sponge regime could create core-mantle boundary temperatures cooler than the melting point of pure Fe, which could promote core convection. Therefore, I conclude that Io lacks a strong dynamo likely because it has a magma ocean with temperatures too high for convection. However, the possibility that Io’s mantle is a magma sponge suggests the importance for future missions to investigate the state of Io’s magnetic field.
Details
Title
- Investigating the Interior of Io: Constraining Scenarios of Its Internal Structure
Contributors
- Lunetto, Sarah (Author)
- O'Rourke, Joseph (Thesis director)
- Walker, Sara (Committee member)
- Barrett, The Honors College (Contributor)
- School of Earth and Space Exploration (Contributor)
Date Created
The date the item was original created (prior to any relationship with the ASU Digital Repositories.)
2024-05
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