Host: The Japanese Society for Planetary Sciences: Local Organizing Committee for 2007 Fall Meeting
The origin and thermal evolution of iron meteorites are important topic to study since they are one of the most oldest material in the solar system we can obtain. According to analysis of isotopic chronology system, they have been separated from silicate within a few myr after CAI formation. On the other hand, Widmanstätten patterns tell us the cooling rate at around 800K.
In this study, we construct a develop model on thermal evolution of planets with ra-dius of 1—100km taking into account melting and silicate-metal separation. Our results show metallic core formed as long as the size of silicate grains is larger than 50μm, and cooling rate as slow as 100 K/myr is achieved if the radius of planet is larger than about 20 km.