date: 2011 March 2 (Wed) 10:00-11:00
room: Kobe University, Science and Technology Research Building #4-809
speaker: Kosuke Kurosawa (The University of Tokyo)
organizer: Akiko Nakamura
title: Phase changes due to hypervelocity impacts
abstract: The planets in the solar system are grown with a number of collisions. The main constituents of planets, such as silicates and water ice, are melted/vaporized by intense shock-heating when peak shock pressures due to hypervelocity impacts are higher than the critical values.
Impact-induced melting leads to metal/rock core formation. In addition, Impact melt rock is one of the most important geologic records because they can be used to constraint impact history in the solar system using radiogenic dating method. Impact-induced vaporization is considered as one of the most important processes on the production of prebiotic organics on the early Earth. Furthermore, recent theoretical studies show that the degree of vaporization due to giant impact and dynamical motion of silicate vapor determines whether the giant impact hypothesis is valid or not.

I stayed at Harvard University on January 2011 because of the G-COE exchange program and started a collaboration research with Dr. S. T. Stewart of Harvard Univ. on impact-induced core formation due to single impact event in the EKB region. In this seminar, I am going to talk about the framework of the research. In addition, I would like to introduce the results of shock vaporization experiments with silicate targets independently conducted by us and Harvard group and to discuss on the formation process of the Moon after a giant impact based on the experimental results.