HR: 1340h
AN: G43A-0790    [Abstracts]
TI: Mercury's Interior Structure and Geodesy
AU: * Van Hoolst, T
EM: tim.vanhoolst@oma.be
AF: Royal Observatory of Belgium, Ringlaan 3, Brussels, 1180 Belgium
AU: * Van Hoolst, T
EM: tim.vanhoolst@oma.be
AF: Institute of Astronomy Katholieke Universiteit Leuven, Celestijnenlaan 200B, Leuven, 3001 Belgium
AB: Interior structure models of Mercury have been calculated with particular focus on the core. Mercury has a very large core, compared to the other terrestrial planets, thought to consist mainly of iron and an unknown amount of sulfur. Thermal evolution models, high pressure data on iron alloys, and the magnetic measurements of Mariner 10 point to a core structure as for the Earth, with a solid inner core and a liquid outer core. We have considered a plausible range in sulfur concentration for the core and constructed Mercury models in different phases of its core evolution, from entirely liquid to entirely solid cores. Data on core material relevant for the pressures and temperatures in Mercury's core is used, and we investigate the effects of sulfur dissolving in the solid inner core. Several geodesy experiments have the potential of providing insight into Mercury's deep interior. Precise measurements of Mercury's obliquity and libration in longitude, along with the harmonic degree 2 gravitational field coefficients will determine both the polar principal moment of inertia of the entire planet and of the mantle, $C$ and $C_m$, respectively. On the other hand, Mercury's solid body tides, which are the largest of the solar system planets, are very sensitive to the core properties, and will be observed by the MESSENGER and BepiColombo missions. We calculated the moments of inertia $C$ and $C_m$ and the tidal reaction of our Mercury models, and studied their sensitivity to several core parameters.
DE: 5430 Interiors (8147)
DE: 6235 Mercury
DE: 1227 Planetary geodesy and gravity (5420, 5714, 6019)
SC: Geodesy [G]
MN: 2004 AGU Fall Meeting