Work

14N/15N abundance ratio toward massive star-forming regions with different Galactic distances

Year: 2025

Type: article

Abstract: 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.

Source: Astronomy and Astrophysics

DOI: 10.1051/0004-6361/202452851

Authors: Chang Ruan, Junzhi Wang, Chao Ou, Juan Li, Bo Zhang

Institutions: Guangxi University, Chinese Academy of Sciences, Shanghai Astronomical Observatory

Language: English

Topic: Astrophysics and Star Formation Studies

Subfield: Astronomy and Astrophysics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $1,865

Funder: National Natural Science Foundation of China