火星から脱出する水素は 季節的な砂嵐による水の移動によって引き起こされます
Shane W Stone1, Roger V Yelle2, Mehdi Benna3,4
1Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85711, USA. stone@lpl.arizona.edu.
まとめ
火星は水を失いますが 以前はそう考えられませんでした 水蒸気は,直接上層大気圏に移動し,そこで
科学分野:
- 惑星科学
- 大気科学
- 天体生物学
背景:
- 火星はかつて水分を豊富に持っていたが,そのほとんどは宇宙に失われてしまった.
- 現在のモデルでは 水の損失から 分子水素が上層大気圏に拡散することを示唆しています
- この水素は原子水素に分解され 脱出します
研究 の 目的:
- 火星の大気中の水分流出の 主なメカニズムを調査する
- 上層大気圏への水蒸気の輸送経路を理解するために
- 火星の気候の進化に 与える影響を定量化するためです
主な方法:
- 火星大気と揮発性進化 (MAVEN) 宇宙船のニュートラルガスとイオン質量スペクトロメーター (NGIMS) のデータを利用した.
- 火星の上層大気中の水と副産物の豊富さと分布を分析した.
- 観測データに基づく水素脱出経路のモデル化
主要な成果:
- 下層大気拡散を回避して,上層大気圏に水蒸気の直接輸送を証明した.
- 南部の夏にピークに達する.
- 2018年の世界的なイベントを含む砂嵐の際の水分量の大幅な増加を記録した.
- この直接的な水輸送が 宇宙への原子水素損失の 主要な経路であると計算しました
結論:
- 火星での水の損失の主なメカニズムは,上層大気圏への水蒸気の直接輸送です.
- 季節の変化や砂嵐は 水の輸送と水素の流出に大きく影響します
- この過程は火星の気候の形成と 寒くて乾燥した惑星への移行に 重要な役割を果たしています
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