Planetary Science Seminar

Abstract: Iron-rich cores are common in the solar system, yet only a few Earth-like planetary bodies maintain active dynamos. With a proportionally much larger core, why is Mercury's magnetic field so much weaker than that of the Earth? How did the Moon keep a long-lived dynamo given the tiny size of its core? And what is the role of core crystallization in sustaining the geodynamo?
In this seminar, I will present recent experimental results on the melting behavior and physical properties of iron-sulfur and iron-carbon systems at high pressures. Depending on its composition and pressure conditions, an iron-rich core may solidify by growing an iron inner core through freezing in the 'heart" or "snowing", or by forming a carbide inner core. The diverse freezing styles would lead to different fates of core dynamos.