Core solidification and dynamo evolution in a mantle-stripped planetesimal

A. Scheinberg, Linda Elkins-Tanton, G. Schubert, D. Bercovici

Research output: Contribution to journalArticle

15 Scopus citations

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 languageEnglish (US)
Pages (from-to)2-20
Number of pages19
JournalJournal of Geophysical Research E: Planets
Volume121
Issue number1
DOIs
StatePublished - Jan 1 2016

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Keywords

  • asteroids
  • core
  • dynamo
  • planetesimals
  • solidification

ASJC Scopus subject areas

  • Geochemistry and Petrology
  • Geophysics
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science

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