Predicted recovery of Mercury's internal structure by MESSENGER

Abstract

Recent Earth-based and forthcoming MESSENGER spacecraft observations of the spin state and gravity field of Mercury will provide the opportunity to determine that planet's internal structure with unprecedented precision. These observations will provide estimates of the dimensionless polar moment of inertia and the ratio of the moment of inertia of the mantle plus crust to that of the planet. In order to understand how well these two parameters will constrain Mercury's internal structure we calculate ∼800,000 Monte Carlo models of the planet's interior. Within the uncertainties currently predicted to be achieved by MESSENGER for these quantities we estimate that the radius and bulk density of an Fe-FeS core and the bulk density of the silicate shell can be determined to within ±23 km, ±147 kg m-3, and ±72 kg m-3, respectively. Copyright 2007 by the American Geophysical Union.