High nitrogen and carbon isotopic ratios in the interstellar comet 3I/ATLAS
13 affiliations
- 1Institute for Astronomy, University of Edinburgh, Royal Observatory, Edinburgh, UK
- 2STAR Institute, University of Liège, Liège (Sart-Tilman), Belgium
- 3Volgenau Department of Physics, United States Naval Academy, Annapolis, MD, USA
- 4Faculty of Science and Engineering, Northumbria University, Newcastle, UK
- 5Physics Department, Edmund C. Leach Science Center, Auburn University, Auburn, AL, USA
- 6Instituto de Astrofísica, Pontificia Universidad Católica de Chile, Macul, Chile
- 7Millennium Nucleus on Young Exoplanets and their Moons (YEMS), Santiago, Chile
- 8Astrochemistry Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD, USA
- 9Department of Physics, Catholic University of America, Washington, DC, USA
- 10Department of Physics, University of Helsinki, Helsinki, Finland
- 11Department of Physics and Astronomy, University of Padova, Padova, Italy
- 12INAF – Osservatorio Astrofisico di Arcetri, Florence, Italy
- 13School of Physical and Chemical Sciences – Te Kura Matū, University of Canterbury, Christchurch, New Zealand
Abstract
Interstellar objects provide a unique opportunity to deepen our understanding of planetary formation by enabling detailed study of material formed around other stars. Their ices contain precious clues about the environment and conditions prevailing in their home system. As fractionation processes can be sensitive to the temperature and radiation environment, isotopic ratios are powerful tracers of the origin and evolution of different species. While isotopic ratios have been measured in Solar System comets, previously detected interstellar objects have been too faint to measure isotopic ratios. Here we report the measurement of two ratios in 3I/ATLAS from observations of the CN molecule: 12 C/ 13 C = 151−44+110 151 - 44 + 110 and 14 N/ 15 N = 363−153+633 36 3 − 153 + 633 . The 14 N/ 15 N is higher than the value of ~150 usually measured for Solar System comets, close to the values measured in the interstellar medium, prestellar phases or outside of protoplanetary disks. The 12 C/ 13 C is higher than the values usually measured for Solar System comets and in the local interstellar medium. These measurements are compatible with an origin of 3I in the outer disk around an older low-metallicity star, providing potential insights into the likelihood and efficiency of planetesimal formation around such stars.
Related
- Characterization of the anisotropic dust activity of interstellar comet 3I/ATLAS
- High-resolution optical spectroscopy reveals the distinctive volatile composition of the interstellar comet 3I/ATLAS
- Origin and evolution of NiI and FeI in the coma of the interstellar comet 3I/ATLAS throughout its trajectory
- Spectral Energy Distribution and Polarimetric Properties of Dust in the Interstellar Comet 3I/ATLAS
- JWST/MIRI Finds ISM-like Amorphous Silicates in Interstellar Comet 3I/ATLAS
BibTeX
@article{opitom2026high,
title = {{High nitrogen and carbon isotopic ratios in the interstellar comet 3I/ATLAS}},
author = {Cyrielle Opitom and Jean Manfroid and Damien Hutsemékers and Emmanuël Jehin and Matthew M. Knight and Krishnakumar Aravind and Léa Ferellec and Dennis Bodewits and Viviana Veloso Guzmán and Martin Cordiner and Rosemary C. Dorsey and Fiorangela La Forgia and Manuela Lippi and B. P. Murphy and C. Snodgrass and Michele Bannister},
journal = {Nature Astronomy},
year = {2026},
month = jul,
doi = {10.1038/s41550-026-02921-7},
url = {https://doi.org/10.1038/s41550-026-02921-7},
note = {CC BY},
}
RIS
TY - JOUR
TI - High nitrogen and carbon isotopic ratios in the interstellar comet 3I/ATLAS
AU - Cyrielle Opitom
AU - Jean Manfroid
AU - Damien Hutsemékers
AU - Emmanuël Jehin
AU - Matthew M. Knight
AU - Krishnakumar Aravind
AU - Léa Ferellec
AU - Dennis Bodewits
AU - Viviana Veloso Guzmán
AU - Martin Cordiner
AU - Rosemary C. Dorsey
AU - Fiorangela La Forgia
AU - Manuela Lippi
AU - B. P. Murphy
AU - C. Snodgrass
AU - Michele Bannister
PY - 2026
DA - 2026/07/06
JO - Nature Astronomy
DO - 10.1038/s41550-026-02921-7
UR - https://doi.org/10.1038/s41550-026-02921-7
AB - Interstellar objects provide a unique opportunity to deepen our understanding of planetary formation by enabling detailed study of material formed around other stars. Their ices contain precious clues about the environment and conditions prevailing in their home system. As fractionation processes can be sensitive to the temperature and radiation environment, isotopic ratios are powerful tracers of the origin and evolution of different species. While isotopic ratios have been measured in Solar System comets, previously detected interstellar objects have been too faint to measure isotopic ratios. Here we report the measurement of two ratios in 3I/ATLAS from observations of the CN molecule: 12 C/ 13 C = 151_−44^+110 151 - 44 + 110 and 14 N/ 15 N = 363_−153^+633 36 3 − 153 + 633 . The 14 N/ 15 N is higher than the value of ~150 usually measured for Solar System comets, close to the values measured in the interstellar medium, prestellar phases or outside of protoplanetary disks. The 12 C/ 13 C is higher than the values usually measured for Solar System comets and in the local interstellar medium. These measurements are compatible with an origin of 3I in the outer disk around an older low-metallicity star, providing potential insights into the likelihood and efficiency of planetesimal formation around such stars.
SN - 2397-3366
ER -