Measurements of the 12C/13C ratio in Planetary Nebulae and implications for stellar evolution
Abstract
We present the results of a study aimed at determining the 12C/13C ratio in two samples of planetary nebuale (PNe) by means of mm-wave observations of 12CO and 13CO. The first group includes six PNe which have been observed in the 3He+ hyperfine transition; the other group consists of 23 nebulae with rich molecular envelopes. We have determined the isotopic ratio in 14 objects and the results indicate a range of values between 9 and 23. In particular, three PNe have ratios well below the value predicted by standard evolutionary models (about 20), indicating that some extra-mixing process has occurred in these stars. We briefly discuss the implications of our results for standard and nonstandard stellar nucleosynthesis.
Keywords
Cite
@article{arxiv.astro-ph/9710040,
title = {Measurements of the 12C/13C ratio in Planetary Nebulae and implications for stellar evolution},
author = {F. Palla and D. Galli and R. Bachiller and M. Perez Gutierrez},
journal= {arXiv preprint arXiv:astro-ph/9710040},
year = {2022}
}
Comments
8 pages, LaTeX, 1 Postscript figure. to appear in The Primordial Nuclei and Their Galactic Evolution, eds. N. Prantzos, M. Tosi, R. von Steiger (Kluwer: Dordrecht)