Issue |
A&A
Volume 695, March 2025
|
|
---|---|---|
Article Number | L6 | |
Number of page(s) | 8 | |
Section | Letters to the Editor | |
DOI | https://doi.org/10.1051/0004-6361/202452851 | |
Published online | 28 February 2025 |
Letter to the Editor
14N/15N abundance ratio toward massive star-forming regions with different Galactic distances
1
Guangxi Key Laboratory for Relativistic Astrophysics, School of Physical Science and Technology, Guangxi University, Nanning 530004, China
2
Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Road, Shanghai 200030, China
3
Key Laboratory of Radio Astronomy, Chinese Academy of Sciences, Nanjing 210033, China
⋆ Corresponding authors; junzhiwang@gxu.edu.cn; changruan@st.gxu.edu.cn
Received:
2
November
2024
Accepted:
3
February
2025
Context. The abundance ratio of 14N/15N is, in principle, a powerful tool for tracing stellar nucleosynthesis.
Aims. This work aims to measure and analyze (14N/15N) × (13C/12C) and 14N/15N abundance ratios in massive star-forming regions across a range of galactocentric distances to provide constraints on galactic chemical evolution (GCE) models.
Methods. We present H13CN and HC15N J = 2–1 results toward 51massive star-forming regions obtained with the Institut de Radioastronomie Millimétrique (IRAM) 30 meter telescope. We used these results to derive (14N/15N) × (13C/12C) abundance ratios as well as 14N/15N ratios using the double isotope method.
Results. We find an overall decreasing trend in the (14N/15N) × (13C/12C) abundance ratio and an increasing trend in the 14N/15N ratio with increasing galactocentric distance (DGC), which provides a good constraint for the GCE model based on high signal to noise ratio measurements. While the predicted (14N/15N) × (13C/12C) ratios between 6 and 12 kpc determined using current GCE models are consistent with our observational results, the ratios from models for DGC less than 6 kpc are significantly higher than the observational results, which indicates GCE models for 14N/15N and/or 13C/12C ratios need to be updated for at least this range.
Key words: stars: evolution / ISM: abundances / Galaxy: abundances / Galaxy: evolution
© The Authors 2025
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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