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超冷たい小惑星の周りの放射線帯が確認されました
Melodie M Kao1,2, Amy J Mioduszewski3, Jackie Villadsen4
1Department of Astronomy & Astrophysics, University of California, Santa Cruz, CA, USA. mmkao@ucsc.edu.
Nature
|May 15, 2023
まとめ
天文学者は 超冷たい矮星の周りの 放射帯を発見しました 木星と同じです この発見は予測を裏付け 磁気帯は惑星や星の磁気圏に 共通していることを示唆しています
科学分野:
- 天文学と天体物理学
- 惑星科学
- 恒星物理学
背景:
- 地球や木星のような 惑星の磁気圏に存在する 放射線帯は 磁場に閉じ込められた エネルギーのある粒子の領域です
- 茶色矮星を含む超冷たい矮星は,惑星のような放射能と磁気圏の活動を示し,複雑な磁気環境を示唆しています.
- 以前の仮説では,超冷たい矮星からの静止放射は,冠状フレアに関連している可能性があるが,経験的なフレア関係は常に満たされていない.
研究 の 目的:
- 高解像度画像を用いて超低温矮星 LSR J1835+3259からの静止放射の性質を調査する.
- 惑星の放射線帯のような構造から発生するかどうかを判断する.
- 超冷たい矮星における放射線帯の理論的予測と 恒星の磁気圏への影響を確認する.
主な方法:
- 8.4GHzの超低温矮星 LSR J1835+3259の高解像度無線画像
- 空間的に解明された放射構造の分析.
- 観測された形状と推定された粒子のエネルギーを,特に木星の既知の惑星放射線帯と比較する.
主要な成果:
- LSR J1835+3259からの空間的に解明された静止無線放射は,安定した,双葉の,軸対称構造を示しています.
- 観測された形状は木星の放射線帯に 驚くほど似ています
- 推定された電子エネルギー (15 MeV) は,星の磁気二極によって制限された木星の放射線帯で見つかったものと一致しています.
結論:
- この研究は,超冷たい矮星の周りの放射線帯の直接的な証拠を提供し,理論的な予測を確認しました.
- これらの発見は,惑星から星まで,幅広い天体の磁気圏で放射線帯が一般的な現象であることを示唆しています.
- この結果は,回転磁気二極を様々な恒星型で非熱的電波放射を生成するメカニズムとして再検討することを支持する.
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