C15N in Diffuse Molecular Clouds
Abstract
We report the first detection of C15N in absorption in diffuse molecular gas from a detailed examination of archival VLT/UVES data covering the CN lines near 3875 Å. Absorption from the C15N isotopologue is detected in three out of the four directions studied and appears as a very weak feature between the main 12CN and 13CN absorption lines. Column densities for each CN isotopologue are determined through profile fitting, after accounting for weak additional line-of-sight components, which are observed in CH and CH+. The weighted mean value of C14N/C15N for the three sight lines with detections of C15N is 277±16, in very good agreement with the terrestrial 14N/15N ratio of 272. Our results help to clarify the situation regarding the nitrogen isotope ratio in the solar neighborhood, with important implications for interstellar chemistry and Galactic chemical evolution.
- Publication:
-
American Astronomical Society Meeting Abstracts #224
- Pub Date:
- June 2014
- Bibcode:
- 2014AAS...22422004F