Abstract
The physical processes active during the crystallization of a low-pressure, low-gravity planetesimal core are poorly understood but have implications for asteroidal magnetic fields and large-scale asteroidal structure. We consider a core with only a thin silicate shell, which could be analogous to some M-type asteroids including Psyche, and use a parameterized thermal model to predict a solidification timeline and the resulting chemical profile upon complete solidification. We then explore the potential strength and longevity of a dynamo in the planetesimal's early history. We find that cumulate inner core solidification would be capable of sustaining a dynamo during solidification, but less power would be available for a dynamo in an inward dendritic solidification scenario. We also model and suggest limits on crystal settling and compaction of a possible cumulate inner core.
Original language | English (US) |
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Pages (from-to) | 2-20 |
Number of pages | 19 |
Journal | Journal of Geophysical Research: Planets |
Volume | 121 |
Issue number | 1 |
DOIs | |
State | Published - Jan 2016 |
Keywords
- asteroids
- core
- dynamo
- planetesimals
- solidification
ASJC Scopus subject areas
- Geochemistry and Petrology
- Geophysics
- Earth and Planetary Sciences (miscellaneous)
- Space and Planetary Science