早期太阳系中氨基酸的多重形成途径基于小行星Bennu样本中的碳和同位素
Allison A Baczynski1, Ophélie M Mcintosh1, Danielle N Simkus2,3,4
1Department of Geosciences, Pennsylvania State University, University Park, PA 16802.
概括
小行星本努的样本揭示了独特的有机分子,这表明它们的起源与像默奇森这样的石有所不同. 这些发现为早期太阳系和生命起源提供了线索.
科学领域:
- 天体化学是天体化学.
- 宇宙化学 宇宙化学
- 生命的起源研究 生命的起源研究
背景情况:
- 小行星本努的样本含有有机分子,对于前生物化学至关重要.
- 对地外有机物质的同位素分析揭示了形成和改变的历史.
- 了解这些分子是解读生命起源的关键.
研究的目的:
- 在Bennu和Murchison样本中对氨基酸进行皮科莫拉级同位素分析.
- 为了比较分子内碳同位素模式和同位素值.
- 研究外星物体中有机分子形成的不同途径.
主要方法:
- 稳定的同位素测量 (分子内 δ 13 C,分子平均 δ 13 C, δ 15 N) 的氨基酸,化物和.
- 分析来自小行星贝努 (OSIRIS-REx任务) 和默奇森石的样本.
- 敏感同位素分析的最先进的技术.
主要成果:
- 在Bennu中糖氨酸的分子内碳同位素模式与Murchison显著不同.
- 在Bennu氨基酸中观察到高N丰富的δN值 (+170到277‰).
- 在Bennu (Δ = 87‰) 中,D-和L-谷氨酸之间的δ15N值存在显著差异.
结论:
- 默奇森的甘氨酸可能是通过斯特雷克的合成形成的,而本努的甘氨酸可能是从原始冰中的激进-激进反应中形成的.
- 贝努的同位素标志表明,它是在太阳系寒冷的外部形成,并通过改变保留.
- 氨基酸同位素的奇拉差异挑战了对异位素均性之间的异位素均性的假设.
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