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クラシックなnova V339 Del (Nova Delphini 2013) で爆発的なリチウム生産が行われている
Akito Tajitsu1, Kozo Sadakane2, Hiroyuki Naito3
1Subaru Telescope, National Astronomical Observatory of Japan, 650 North A'ohoku Place, Hilo, Hawaii 96720, USA.
Nature
|February 20, 2015
まとめ
科学者たちは,ノヴァでベリリウム-7 (7Be) を検出し,それはリチウム-7 (7Li) に分解した. これは,新星がかなりの量のリチウムを生成するという直接的な証拠を提供しており,これは天体物理学における長年の疑問である.
科学分野:
- * 天体物理学
- * 核天体物理学
- * 恒星の進化について
背景:
- * リチウム (Li) の起源とその生産メカニズムは不明のままである.
- *既存のモデルは,ビッグバン核合成,宇宙線,進化した星,新星,超新星からの貢献を示唆しています.
- *以前の研究では,赤い巨星,アシンプトティック・ジャイアント・ブランチ (AGB) 星,そして新星において,重要なリチウム生成が示されていたが,直接的な観測証拠は欠けていた.
研究 の 目的:
- * 古典的な新星爆発におけるリチウムの生成を調査する.
- * 恒星物体から恒星間介質へのリチウムの供給に関する直接的な観測証拠を提供するため.
主な方法:
- * クラシックな新星V339 Delphini (Nova Delphini 2013) の近紫外線観測を用いたスペクトル分析.
- * 放射性同位体ベリリウム-7 (7Be) の非常に青にシフトした共振線の検出.
主要な成果:
- * 爆発後38~48日後のノヴァ・デルフィーニ2013のスペクトルで単一の電離ベリリウム-7 (7Be) の検出.
- *ベリリウム-7 (7Be) は,新星爆発中のアルファ捕獲反応 (3He(α,γ) 7Be) によって形成された.
- *ベリリウム-7 (7Be) はリチウム-7 (7Li) に分解し,半減期は53.22日である.
結論:
- * クラシックノヴァでの7Beの検出は,これらのイベントでリチウム生成の直接的な証拠を提供します.
- *この発見は,新星が銀河のリチウムの重要な源であるという理論的予測を支持する.
- *この研究は,恒星核合成と化学進化の重要な問題に取り組んでいます.
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