  This study uses cool dwarfs as sources with which to probe fluorine
abundances via HF. This molecule is detected for the first time in young K-M
dwarf members of an OB association. Fluorine, oxygen, and carbon abundances
were derived from the HF(1--0) R9 line along with samples of OH and CO
vibration-rotation lines present in high-resolution infrared spectra observed
with the Phoenix spectrograph on the Gemini South Telescope. The fluorine and
oxygen results obtained for these targets, still in the pre-main-sequence stage
of evolution, agree well with the general trend defined for the Milky Way disk;
the latter being deduced from observations of more evolved giant stars. In
addition, the carbon and oxygen abundances obtained for the studied stars
overlap results from previous studies of the more massive OB stars and FG dwarf
members of the Orion Nebula Cluster. We conclude from this agreement that the
fluorine abundances derived for the Orion K-M dwarfs (when there is no
conspicuous evidence of disks) can be considered a good representation of the
current fluorine abundance value for the Milky Way disk.
