マグネシウムの同位体 蓄積による蒸気損失が惑星の組成を形作る証拠
Remco C Hin1, Christopher D Coath1, Philip J Carter2
1School of Earth Sciences, University of Bristol, Wills Memorial Building, Queens Road, Bristol BS8 1RJ, UK.
Nature
|September 30, 2017
まとめ
原始的な隕石よりも重いマグネシウムの同位体を示しています この違いは,星雲や核のプロセスではなく,惑星積層中の蒸気損失から生じた可能性が高い.
科学分野:
- 惑星科学
- 宇宙化学
- 同位体地化学
背景:
- 異なる惑星は,原始的なコンドリート隕石と化学的に異なる.
- 惑星の揮発性減退の起源 (増積と霧状分化) は依然として議論されている.
- 同位体組成は惑星の形成過程の洞察を提供します.
研究 の 目的:
- 惑星の化学分化の起源を調査する
- 揮発性の枯渇が蓄積または霧状のプロセスによるかどうかを判断する.
- 微分体におけるマグネシウムの同位体組成を分析する.
主な方法:
- 測定誤差を減らすために改良された分析方法を開発した.
- 異なる惑星体とコンドリート隕石のマグネシウム同位体組成を測定した.
- 惑星形成段階における同位体の分断をモデル化した.
主要な成果:
- 研究されたすべての微分体は,コンドリート隕石と比較してより重いマグネシウム同位体組成を示している.
- 太陽雲の凝縮,核形成,またはシリケート分化中の分断は,観測されたマグネシウム同位体の変動を説明しません.
- 惑星積層中の蒸気脱出による同位体の分断は,実行可能な説明を提供します.
結論:
- 惑星におけるマグネシウムの同位体変動は,蓄積過程における有意な蒸気損失によって最もよく説明される.
- 液体蒸気分化と脱出を含むこのメカニズムは,シリコンと鉄の同位体にも影響を及ぼします.
- 観測された元素と同位体組成は,成長過程で惑星質から約40%の蒸気損失を伴う.
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