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| Titel |
Mercury's inner core size and core crystallization regime |
| VerfasserIn |
Mathieu Dumberry, Attilio Rivoldini |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250102828
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| Publikation (Nr.) |
 EGU/EGU2015-2232.pdf |
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| Zusammenfassung |
| Earth-based radar observation of Mercury’s rotation vector combined with gravity
observation by the MESSENGER spacecraft yield a measure of Mercury’s moment of inertia
and the amplitude of the 88-day libration of its silicate shell. These two geodetic constraints
provide information on Mercury’s interior structure, including the presence of a
fluid core, the radius of the core-mantle boundary and the bulk densities of the
core and mantle. In this work, we show how they further provide information on
the size of the solid inner core and on the crystallization regime of the fluid core.
If Mercury’s fluid core is a Fe-FeS alloy, the largest inner core compatible with
geodetic observations is 1325 ± 250 km. The crystallization scenario that best fits
the observations involves the formation of Fe-snow within the fluid core. Snow
formation can be restricted to a thin layer or can occupy the whole of the fluid
core depending on inner core size and initial sulfur concentration. Our results offer
important constraints for dynamo models of Mercury, but also advocate for the further
development of models that incorporate the various features of snow formation. |
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