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Nils Ryde

Nils Ryde


Nils Ryde

Fluorine in the Solar Neighborhood: Is It All Produced in Asymptotic Giant Branch Stars?


  • Henrik Jönsson
  • Nils Ryde
  • G. M. Harper
  • M. J. Richter
  • K. H. Hinkle

Summary, in English

The origin of "cosmic" fluorine is uncertain, but there are three proposed production sites/mechanisms for the origin: asymptotic giant branch (AGB) stars, nu nucleosynthesis in Type II supernovae, and/or the winds of Wolf-Rayet stars. The relative importance of these production sites has not been established even for the solar neighborhood, leading to uncertainties in stellar evolution models of these stars as well as uncertainties in the chemical evolution models of stellar populations. We determine the fluorine and oxygen abundances in seven bright, nearby giants with well determined stellar parameters. We use the 2.3 mu m vibrational-rotational HF line and explore a pure rotational HF line at 12.2 mu m. The latter has never been used before for an abundance analysis. To be able to do this, we have calculated a line list for pure rotational HF lines. We find that the abundances derived from the two diagnostics agree. Our derived abundances are well reproduced by chemical evolution models including only fluorine production in AGB stars and, therefore, we draw the conclusion that this might be the main production site of fluorine in the solar neighborhood. Furthermore, we highlight the advantages of using the 12 mu m HF lines to determine the possible contribution of the. process to the fluorine budget at low metallicities where the difference between models including and excluding this process is dramatic.


  • Lund Observatory

Publishing year





Astrophysical Journal Letters





Document type

Journal article


IOP Publishing


  • Astronomy, Astrophysics and Cosmology


  • molecular data
  • solar neighborhood
  • stars: abundances




  • VR-projektbidrag: Infraröd spektroskopi - ett nytt fönster mot galaktisk astronomi
  • PhD project: The cosmic origin of fluorine and sulphur: Infrared spectroscopic studies of red giants


  • ISSN: 2041-8213