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C-12/C-13 isotope ratio across the Galaxy from observations of C-13/O-18 in molecular clouds
Abstract
The carbon isotopic ratio across the Galaxy was studied by observing nine interstellar clouds in the doubly rare isotope of carbon monoxide, C-13/O-18, and in the rare isotopic species C-12/O-18. The goal in this study was to improve the data from optically thin carbon monoxide emissions. A systematic gradient is found in the C-12/C-13 isotopic ratio across the Galaxy, ranging from about 30 in the inner part at 5 kpc to about 70 at 12 kpc, with a Galactic center value of 24. Near the solar radius the average ratio is 57, but it is somewhat larger, about 67, in Orion. Carbon monoxide isotopic ratios are smaller than those of formaldehyde, but they have roughly the same slope across the Galaxy. The result of 57 for the local CO ratio lies between the values from various CH(+) absorption measurements.
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Cited by
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Abundance Anomalies and Rotational Evolution of Low‐Mass Red Giants: A Maximal Mixing Approach
Chaname, J., Pinsonneault, M., & Terndrup, D. M. (2005) · The Astrophysical Journal · doi:10.1086/432410 · Cited by 69
A CO funnel in the Galactic centre: Molecular counterpart of the northern Galactic chimney
Veena, V. S., Riquelme, D., Kim, W.-J., Menten, K. M., Schilke, P., Sormani, M. C., Banda-Barragán, W. E., Wyrowski, F., Fuller, G. A., & Cheema, A. (2023) · Astronomy & Astrophysics · doi:10.1051/0004-6361/202346702 · Cited by 14
“Various studies have investigated variations in 12C/13C across the Galactic disc (Langer & Penzias 1990; Milam et al. 2005; Jacob et al. 2020; Yan et al. 2023).”
Background
Metadata
- Authors
- Langer, W. D., & Penzias, A. A.
- Venue
- The Astrophysical Journal
- Publisher
- American Astronomical Society
- Published
- 1990-07
- Volume
- 357
- Pages
- 477
- ISSN
- 0004-637X (ISSN-L)
- 1538-4357
- OpenAlex
- W1985666257
- Cited by
- 333
- References
- 0
- FWCI
- 6.95
- Type
- journal article
- Language
- en
- Open access
- closed
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- CoChat. (2026). Citation check: C-12/C-13 isotope ratio across the Galaxy from observations of C-13/O-18 in molecular clouds. https://app.cochat.ai/papers/10.1086/168935
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- Langer, W. D., & Penzias, A. A. (1990). C-12/C-13 isotope ratio across the Galaxy from observations of C-13/O-18 in molecular clouds. The Astrophysical Journal. https://doi.org/10.1086/168935
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