MESSENGERの軌道観測から見た水星の地球規模の磁場
Brian J Anderson1, Catherine L Johnson, Haje Korth
1The Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA. brian.anderson@jhuapl.edu
Science (New York, N.Y.)
|October 1, 2011
まとめ
水星の磁場は,回転軸から北に偏り,磁軸は傾いている. この内部磁場は,オフセット二極体として最もよく表現され,惑星モーメントは195 ± 10 nT·R (M) 3.
科学分野:
- 惑星科学は惑星科学である.
- 地質物理学 地質物理学とは地質物理学です.
- 宇宙物理学 宇宙物理学
背景:
- 水星には地球規模の磁場があり,これは地上の惑星では珍しい特徴です.
- 水星の磁場を理解することは,その内部ダイナモと宇宙環境を理解するために不可欠です.
研究 の 目的:
- MESSENGER宇宙船のデータを用いて水星の内部磁場を特徴づけるために.
- 水星の磁気二極の偏移と方向を決定するために.
- 惑星の磁気モメントを定量化するために.
主な方法:
- マグネトメーターデータから内外磁場貢献を分離する.
- 内部フィールドをスピン・アライネッド・オフセット・ディポールとしてモデル化.
- 放射性磁場構成要素のゼロを特定することによって磁界赤道をマッピングする.
- 外場モデルを定義するために磁気断絶の交差点を利用する.
主要な成果:
- 磁界赤道は地理赤道から484 ± 11 km北に偏っています.
- 水銀の磁気軸は,その回転軸に対して3°未満に傾いている.
- 最適な惑星磁気モーメントは195 ± 10ナノテスラ-R (M) 3.
結論:
- 水星の内部磁場は,オフセット二極モデルによって最もよく説明されます.
- 北への偏移とわずかな傾きは,惑星のダイナモプロセスについての洞察を提供します.
- MESSENGERのデータは,水星の固有の磁場に関する私たちの理解を大幅に洗練しました.
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