New constraints on the delivery of cometary water and nitrogen to Earth from the ¹⁵N/¹⁴N isotopic ratio

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• 作者：Damien Hutsemé ; kers ; Jean Manfroid ; Emmanuë ; l Jehin ; Claude Arpigny
• 关键词：Comets ; Earth ; Origin ; Solar System
• 刊名：Icarus
• 出版年：2009
• 出版时间：November 2009
• 年：2009
• 卷：204
• 期：1
• 页码：346-348
• 全文大小：1626 K

文摘

New independent constraints on the amount of water delivered to Earth by comets are derived using the ¹⁵N/¹⁴N isotopic ratio, measured to be roughly twice as high in cometary CN and HCN as in the present Earth. Under reasonable assumptions, we find that no more than a few percent of Earth’s water can be attributed to comets, in agreement with the constraints derived from D/H. Our results also suggest that a significant part of Earth’s atmospheric nitrogen might come from comets. Since the ¹⁵N/¹⁴N isotopic ratio is not different in Oort-cloud and Kuiper-belt comets, our estimates apply to the contribution of both types of objects.