University of Cambridge > Talks.cam > DAMTP Astro Lunch > A topsy-turvy world: dynamo generation by top-down solidification of planetesimals

A topsy-turvy world: dynamo generation by top-down solidification of planetesimals

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Modern paleomagnetic measurements of asteroid fragments indicate that magnetic field generation was not uncommon in the early solar system, with many smaller bodies exhibiting strong magnetic fields lasting 10-20 Ma. For smaller planetesimals, the mode of solidification is from the top down, in contrast to our current experience of magnetic field generation on Earth. Since thermal convection is likely short lived, solidification from the top down presents a challenge to current models of magnetic field generation. Here we discuss the possibility of magnetic field generation through stirring driven by the episodic delimitation of a viscous iron crust, both in the limit of a pure iron planetesimal and where sulphur impurities are present.

This talk is part of the DAMTP Astro Lunch series.

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