Using the thermal pressure to compute the physical properties of terrestrial planets

Abstract

The density and temperature profiles of a planet's interior are calculated using a set of differential equations defining the major thermal and mechanical variables of a planet. One of these equations, the equation of state (EOS), is perhaps unique, because the density and volume effects are separated into two independent functions. The temperature-dependent part of the EOS is found from high-temperature properties measured on minerals at one atmosphere. The volume-dependent part of the EOS requires parameters determined by high-pressure experiments at room temperature. The density profile of the earth found from this relatively simple model matches the density profile determined from seismic models quite well. The temperature profile of the earth determined by this model agrees well with recently published temperature profiles. Temperature and density profiles of Mercury, Mars, and the Moon are found using assumed physical properties of the planets' outer mantles and using an assumed thickness of the planets' lithospheres.