Statistical Study of the Probability of Titan Being in the Solar Wind or in Saturn's Magnetosheath

We present the results of a statistical study of the location of Titan relative to the bow shock and the magnetopause of Saturn's magnetosphere. Using statistical distributions of solar wind ram pressure at Saturn's orbit and the dependence of the magnetosphere's boundaries on this pressure we are able to calculate the probability of finding Titan in the solarwind, the magnetosheath or the magnetosphere for each point along its orbit. As a preliminary example consider Titan at the sub-solar point for 2004 solar wind conditions. We find that Titan would have spent 56.7% of its time in the magnetosphere, 42.1% in the magnetosheath and 1.3% in the solarwind for these conditions when at the sub-solar point. We will present statistics for Titan at a set of local times along its orbit as well as integrated over its entire orbit. We obtain solar wind conditions at the orbit of Saturn by propagating ACE and other spacecraft measurements of the solar wind conditions at the Earth radially outward using a 1D MHD model. The propagation is validated against Voyager, Pioneer and Cassini data. For our calculations, we use different models for the shape of the bow shock and magnetopause. These include the traditional Slavin model as well as a new boundary model generated by fitting geometric surfaces to a global 3D MHD model of Saturn's magnetosphere.