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Measurements of the 12C/13C ratio in Planetary Nebulae and implications for stellar evolution

F. Palla·D. Galli·R. Bachiller·M. Perez Gutierrez
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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.

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F. Palla, D. Galli, R. Bachiller, M. Perez Gutierrez. 1997-10-03. Measurements of the 12C/13C ratio in Planetary Nebulae and implications for stellar evolution. https://doi.org/10.1007/978-94-011-5116-0_18

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