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Single-Molecule Imaging of Nuclear Transport
Published on: June 9, 2010
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最近の超新星が太陽の近くにある場所をモデル化 (60) Fe輸送
D Breitschwerdt1, J Feige1, M M Schulreich1
1Department of Astronomy and Astrophysics, Berlin Institute of Technology, Hardenbergstraße 36, 10623 Berlin, Germany.
Nature
|April 15, 2016
まとめ
2つの超新星が,太陽系近くで爆発し, 約230万年前と150万年前に, 深海の地殻に鉄-60 (60Fe) の痕跡を残しました. これらの出来事がローカル・バブルの形成に寄与した可能性が高い.
科学分野:
- 天体物理学
- 宇宙線物理学
- 地化学
背景:
- 深海の地殻には放射性同位体鉄-60 (60Fe) が含まれており,これは太陽の近隣にある過去の超新星現象を示しています.
- ローカル・バブルは 太陽系を囲む 熱い 拡散したプラズマの領域で 複数の超新星から形成されたと考えられています
研究 の 目的:
- 60Fe信号を発生させた 超新星の軌道,質量,爆発時間,位置を計算する.
- 観測された60Fe分布と局所バブルの形成に対する異なる超新星の貢献を決定する.
主な方法:
- 深海の地殻における同位体シグネチャーの分析
- 宇宙線スペクトルの分析
- 超新星の原始軌跡と爆発パラメータのモデリング.
主要な成果:
- 60Fe信号は90-100パーセクの距離にある2つの超新星に起因する.
- 最も近い超新星は230万年前 (l=327°,b=11°) に発生し,その祖先の質量は太陽質量9.2倍であった.
- 2番目の超新星は150万年前 (l=343°,b=25°) に爆発し,その祖先の質量は8.8太陽質量であった.
結論:
- この2つの超新星は 60Fe信号の主要な源です
- 局所バブルの形成は14〜20の超新星群と関連しており,より遠い古いイベントは,半減期が260万年であるため,60Fe信号への貢献が少なくなります.
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