The Abundance of Fluorine in Normal G and K Stars of the Galactic Thin
  Disk
  The abundance of fluorine is determined from the (2-0) R9 2.3358 micron
feature of the molecule HF for several dozen normal G and K stars in the
Galactic thin disk from spectra obtained with the Phoenix IR spectrometer on
the 2.1-m telescope at Kitt Peak. The abundances are analyzed in the context of
Galactic chemical evolution to explore the contributions of supernovae and
asymptotic giant branch (AGB) stars to the abundance of fluorine in the thin
disk. The average abundance of fluorine in the thin disk is found to be [F/Fe]
= +0.23 +/- 0.03, and the [F/Fe] ratio is flat or declines slowly with
metallicity in the range from -0.6 < [Fe/H] < +0.3, within the limits of our
estimated uncertainty. The measured abundance of fluorine and lack of variation
with metallicity in Galactic thin disk stars suggest neutrino spallation in
Type II supernovae contributes significantly to the Galactic fluorine
abundance, although contributions from AGB stars may also be important.
