星間媒介における分岐アルキル分子の検出:イソプロピルシアン化物
Arnaud Belloche1, Robin T Garrod2, Holger S P Müller3
1Max-Planck-Institut für Radioastronomie (MPIfR), Auf dem Hügel 69, 53121 Bonn, Germany. belloche@mpifr-bonn.mpg.de.
まとめ
天文学者は,星間空間で,枝分かれした有機分子であるイソプロピルシアン化物を発見しました. この発見は,アミノ酸にとって不可欠な分岐分子が宇宙で一般的であることを示唆しています.
科学分野:
- アストロケミストリー アストロケミストリー
- 星間媒体の構成 星間媒体の構成
- 有機分子の形成について
背景:
- 恒星間介質 (ISM) で確認された最大の非周期性分子は,直鎖の炭素の骨格を特徴とする有機化合物である.
- ISMでの以前の検出は,主に線形有機分子に焦点を当てていました.
研究 の 目的:
- 枝分かれしたアルキル分子,イソプロピルシアン化物 (i-C3H7CN) の最初の星間検出を報告する.
- この検出が,ISMにおける枝分かれした炭素鎖の分子の豊富さに及ぼす影響を調査する.
- ISMにおける線形および枝分かれした有機分子の両方の形成経路を探求する.
主な方法:
- ISMにおける分子検出のための天文観測.
- 分子形成経路をシミュレートするための天体化学モデリング.
- 枝分かれしたイソプロピルシアン化物と,その直鎖同位体間の豊富さの比較.
主要な成果:
- 星間媒質におけるイソプロピルシアン化物 (i-C3H7CN) の検出.
- イソプロピルシアン化物の豊富さは,その直鎖同位体より0.4倍であることが判明しました.
- アストロケミカルモデルによると,両方の同位体は,異なる経路で,急性添加を経由して,塵の粒氷のマントルに形成される.
結論:
- アイソプロピルシアン化物の検出は,枝分かれした炭素鎖分子がISMで一般的に豊富に存在する可能性があることを示しています.
- アイソプロピルシアン化物の形成には,非末端の炭素に機能群の添加が必要であり,複雑な分子合成の経路を示唆しています.
- この発見は,類似の枝分かれの横鎖構造を持つアミノ酸がISMに存在する可能性を裏付けている.
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