[12C]/[13C] ratios from formaldehyde in the inner galactic disk
Abstract
New formaldehyde measurements toward 6 sources in the inner galactic disk (5 kpc ≤ RGC ≤ 8 kpc) are reported. From measurements of the 110 - 111 line of H212C16O and H213C16O and of the 211 - 212 line of H212C16O, [H212C16O]/[H213C16O] ratios are derived. The average corrected ratio is ≡50 for the inner galactic disk. A decrease in the [12C]/[13C] ratio by a factor of ≡2 compared with the local interstellar medium is qualitatively consistent with predictions from galactic evolution models and the higher metallicity of the gas in the inner galactic disk.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- February 1985
- Bibcode:
- 1985A&A...143..148H
- Keywords:
-
- Carbon 12;
- Carbon 13;
- Forbidden Bands;
- Formaldehyde;
- Galactic Nuclei;
- Milky Way Galaxy;
- Astronomical Models;
- Astronomical Spectroscopy;
- Galactic Evolution;
- Radiative Transfer;
- Ratios;
- Astrophysics