星間介質で形成されたリウグーのサンプルに含まれる多環芳香炭化水素
Sarah S Zeichner1, José C Aponte2, Surjyendu Bhattacharjee1
1Geological and Planetary Science Division, California Institute of Technology, Pasadena, CA 91125, USA.
まとめ
隕石のポリサイクル芳香炭化水素 (PAH) は星間起源を示唆している. 同位体分析では 恒星周辺の熱い環境ではなく 冷たい恒星間雲で形成された PAH が示されています
科学分野:
- 天体化学
- 宇宙化学
- 同位体地化学
背景:
- ポリサイクルアロマティック炭化水素 (PAH) は,星間媒質における重要な炭素媒質である.
- PAHは,星周包膜,星間雲,または塵の粒子の処理など,さまざまな環境で形成される可能性があります.
研究 の 目的:
- 異星人のサンプルで PAH の同位体の性質を分析することで PAH の起源を調査する.
- 同位体成分に基づいてPAHの形成経路を区別する.
主な方法:
- 小惑星Ryuguとマーチソン隕石のサンプルからPAHを抽出する.
- 特定のPAHの二重13C置換組成 (Δ2×13C値) の測定
主要な成果:
- ナフタレン,フローランタン,およびピレンは,ストキャスティック分布で予想されるよりも著しく高いΔ2×13C値を示した.
- これらの高値は,高温の星周環境ではなく,冷たい星間環境で形成されることを示唆しています.
- リウグーのサンプルにおけるフェナントレンとアントラセンは,高温形成と一致する Δ2×13C値を示した.
結論:
- 同位体データは,隕石に含まれる特定のPAHの星間形成を裏付けている.
- 証拠はPAHの二重起源を示唆し,あるものは寒い星間環境で,あるものはより暑い環境で形成される.
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