日本地球惑星科学連合2019年大会

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[E] 口頭発表

セッション記号 S (固体地球科学) » S-IT 地球内部科学・地球惑星テクトニクス

[S-IT25] Planetary cores: Structure, formation, and evolution

2019年5月30日(木) 10:45 〜 12:15 A09 (東京ベイ幕張ホール)

コンビーナ:寺崎 英紀(大阪大学大学院理学研究科)、大谷 栄治(東北大学大学院理学研究科地学専攻)、William F McDonough(University of Maryland College Park)、George Helffrich(Earth-Life Science Institute, Tokyo Institute of Technology)、座長:William McDonough(University of Maryland / Tohoku University)、大谷 栄治(東北大学)

11:00 〜 11:15

[SIT25-07] Ab initio study of Iron-Nickel alloys in Super-Earths cores

*Francois Soubiran1Razvan Caracas1 (1.Ecole normale superieure de Lyon, Laboratoire de Géologie de Lyon, Université Lyon 1, CNRS UMR 5276, Lyon, France)

キーワード:Super-Earth, iron core, Ab initio simulations

Iron-nickel alloys are considered the main components of Earth and Super-Earth cores, which make them crucial systems in order to comprehend the properties of these planets. While the relative nickel content is anticipated to be around 10% in the Earth, this value could differ slightly in other planets because of different host star metallicity and formation history. It is thus important to understand the properties of iron-nickel systems with various compositions in the multi-megabar regime.

While pure iron is anticipated to have hexagonal close packing at high pressure, nickel is expected to have face-centered cubic packing. This means there is a structural change as the composition is modified, which can also mean a limited stability of the solid solutions of iron-nickel.

We will discuss the properties of iron-nickel alloys in the megabar regime as predicted by ab initio simulations. We will examine the relative stability of different iron-nickel solid solution compositions and the interplay of the spin states. After characterizing the properties of these alloys at pressure-temperature conditions relevant for Super-Earth, we will discuss possible consequences their cores.