Fluorine Abundances in Planetary Nebulae
نویسنده
چکیده
We have determined fluorine abundances from the [F II] λ4789 and [F IV] λ4060 nebular emission lines for a sample of planetary nebulae (PNe). Our results show that fluorine is generally overabundant in PNe, thus providing new evidence for the synthesis of fluorine in asymptotic giant branch (AGB) stars. [F/O] is found to be positively correlated with the C/O abundance ratio, in agreement with the predictions of theoretical models of fluorine production in thermally pulsing AGB stars. A large enhancement of fluorine is observed in the Wolf-Rayet PN NGC40, suggesting that high mass-loss rates probably favor the survival of fluorine. Subject headings: ISM: abundances — planetary nebulae: general — line: identification
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