まとめ
火星の窒素は,選択的な大気逃逸により,同位体 (15) N で濃縮されています. 初期の火星は,窒素圧が最大30ミリバールであったかもしれない.
科学分野:
- 惑星科学は惑星科学である.
- 大気化学 大気化学
- イソトープ地球化学 イソトープ地球化学
背景:
- バイキングの測定は,火星の大気中の窒素同位体 (15) N の有意な濃縮を明らかにした.
- この濃縮は,火星の大気流失の過程の歴史を示唆している.
研究 の 目的:
- 火星の窒素の過去の歴史をモデル化するために.
- 火星の大気中の (15) N の濃縮が観察されたことを説明するために.
主な方法:
- バイキングミッションのデータを活用して大気組成を分析する.
- 大気逃亡のモデルを開発し,特に選択的プロセスに焦点を当てます.
- 電子衝突によるN(2) の解離とN(2) の解離性再結合が,大気流失における役割を調査する.
主要な成果:
- (15) Nの濃縮は,選択的な大気脱出メカニズムと一致しています.
- エクソスフィアで形成された素早い原子は,この選択的損失に寄与する.
- 初期窒素 (N(2)) の部分圧は,数ミリバーであったかもしれない.
結論:
- 窒素イソトープの選択的脱出は,現在の火星の大気の形成に決定的な役割を果たしています.
- 表面処理が大気中のHNO2とHNO3の重要な吸収源として機能していた場合,最初の窒素圧力は30ミリバーにまで達した可能性があります.
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