日時 ： ２００９年１０月１６日（金）※16：30～
場所 ： 愛媛大学総合研究棟Ⅰ 4F 共通会議室（理学部構内）
要 旨
It has been long known that the formation of the core transforms gravitational energy into heat and is able to heat up the whole Earth by about 2000 K. However, the distribution of this energy within the Earth is still debated and depends on the core formation process considered. Iron rain in the surface magma ocean is supposed to be the first mechanism of separation for large planets, iron then ponds at the base of the magma ocean. Time scale of the separation can be estimated from falling velocity of the iron phase, which is estimated by numerical simulation. In this study, we made 1D numerical calculations of the whole magma ocean using a parameterization based on 2D and 3D direct numerical simulations of a 10cm-scale emulsion of iron in liquid silicates. This parameterization of drop velocities was used to study the possibility of large-scale overturn of the emulsion by Rayleigh-Taylor instability. Then, we compute the evolution of the thermal structure during the separation of iron phase. The maximum of the temperature is obtained at the boundary between the metal ponds (or the core if the whole planet is liquid) and the silicate. Therefore, the iron pond is thermally stable and the remaining silicate magma ocean is thermally unstable.
問い合わせ先：土屋 卓久 TEL （089）927-8198
E-mail takut@sci.ehime-u.ac.jp
