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Updated: Aug 13, 2026

Automated, High-resolution Mobile Collection System for the Nitrogen Isotopic Analysis of NOx
Published on: December 20, 2016
Anomalous nitrogen isotope ratio in comets
Claude Arpigny1, Emmanuël Jehin, Jean Manfroid
1Institut d'Astrophysique et de Géophysique, Sart-Tilman, Bâtiment B5c, B-4000 Liège, Belgium. Claude.Arpigny@ulg.ac.be
Abstract:
High-resolution spectra of the CN B2 summation operator +-X2 summation operator + (0,0) band at 390 nanometers yield isotopic ratios for comets C/1995 O1 (Hale-Bopp) and C/2000 WM1 (LINEAR) as follows: 165 +/- 40 and 115 +/- 20 for 12C/13C, 140 +/- 35 and 140 +/- 30 for 14N/15N. Our N isotopic measurements are lower than the terrestrial 14N/15N = 272 and the ratio for Hale-Bopp from measurements of HCN, the presumed parent species of CN. This isotopic anomaly suggests the existence of other parent(s) of CN, with an even lower N isotopic ratio. Organic compounds like those found in interplanetary dust particles are good candidates.
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