火星の上層大気中の夜の光と,大気輸送への影響
Jean-Loup Bertaux1, François Leblanc, Séverine Perrier
1Service d'Aéronomie du CNRS/Institut Pierre-Simon Laplace (IPSL), BP.3, 91371, Verrières-le-Buisson, France. bertaux@aerov.jussieu.fr
Science (New York, N.Y.)
|February 1, 2005
まとめ
火星エクスプレスは,火星の夜間大気中の紫外線放射を検出しました. 主に窒素酸化物 (NO) の帯状であるこの夜間光は,大気輸送と凍結による冬の南極地域で最も明るくなります.
科学分野:
- 惑星科学は惑星科学である.
- 大気科学 大気科学
- スペクトロスコーピーは,スペクトロスコーピーを用います.
背景:
- 火星の大気は,太陽放射線によって引き起こされるものを含め,複雑な化学的プロセスを表しています.
- 大気中の排出量を理解することは,惑星の環境を特徴づける上で極めて重要です.
研究 の 目的:
- 火星の大気中の夜間光の放射を検知・分析する.
- これらの大気中の排出物の構成と起源を特定する.
主な方法:
- 火星エクスプレス号の宇宙船に搭載されたSPICAM (火星大気特性の調査のためのスペクトロスコーピー) 紫外線スペクトロメーターを利用した.
- 火星の夜明かりの紫外線スペクトルを分析した.
主要な成果:
- 水素ライマンアルファ放射と窒素酸化物 (NO) のガンマとデルタ帯が火星の夜間大気圏で検出されました.
- NOの排出は,極端なUV光解離によって生成される窒素 (N) と酸素 (O) 原子の再結合によるものです.
- NO排出の強度は,冬の南極夜に最大である.
結論:
- 観測された夜間光は,主に昼間の大気光解離およびその後の輸送から発生するNO排出物で構成されています.
- 冬の南極夜に発生する NO 排出量の増加は,継続的な下向きの航空輸送と地表の凍結によるものである.
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