Far Ultraviolet Spectroscopic Explorer Measurements of Interstellar Fluorine

Abstract

The source of fluorine is not well understood, although core-collapse supernovae, Wolf-Rayet stars, and asymptotic giant branch stars have been suggested. A search for evidence of the ν-process during Type II supernovae is presented. Absorption from interstellar F I is seen in spectra of HD 208440 and HD 209339A acquired with the Far Ultraviolet Spectroscopic Explorer. In order to extract the column density for F I from the line at 954 Å, absorption from H₂ has to be modeled and then removed. Our analysis indicates that for H₂ column densities less than about 3×10²⁰ cm^-2, the amount of F I can be determined from λ954. For these two sight lines, there is no clear indication for enhanced F abundances resulting from the ν-process in a region shaped by past supernovae.

Based on observations made with the NASA/CNES/CSA Far Ultraviolet Spectroscopic Explorer (FUSE), which is operated for NASA by the Johns Hopkins University under NASA contract NAS 5-32985.