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

Abstract

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.

Accepted for publication in ICARUS

References in corpus (4)

• Origin of the Ocean on the Earth: Early Evolution of Water D/H in a Hydrogen-rich Atmosphere
• Large excess of heavy nitrogen in both hydrogen cyanide and cyanogen from comet 17P/Holmes
• The CN isotopic ratios in comets
• The 16OH/18OH and OD/OH isotope ratios in comet C/2002 T7 (LINEAR)

Cited by in corpus (6)

• Isotopic ratios of H, C, N, O, and S in comets C/2012 F6 (Lemmon) and C/2014 Q2 (Lovejoy)
• A Compound model for the origin of Earth's water
• Terrestrial Planet Formation During the Migration and Resonance Crossings of the Giant Planets
• Geochemical and planetary dynamical views on the origin of Earth's atmosphere and oceans
• Possible Atmospheric Diversity of Low Mass Exoplanets, some Central Aspects
• Late Delivery of Nitrogen to Earth