Interstellar Deuterium, Nitrogen, and Oxygen Abundances toward BD +28o4211: Results from the FUSE Mission

High resolution far-ultraviolet spectra of the O-type subdwarf BD +28 4211were obtained with the Far Ultraviolet Spectroscopic Explorer (FUSE) to measurethe interstellar deuterium, nitrogen, and oxygen abundances in this direction.The interstellar D I transitions are analyzed down to Lyman iota at 920.7 A.The star was observed several times at different target offsets in thedirection of spectral dispersion. The aligned and coadded spectra have highsignal-to-noise ratios (S/N =50-100). D I, N I, and O I transitions wereanalyzed with curve-of-growth and profile fitting techniques. A model ofinterstellar molecular hydrogen on the line of sight was derived from H2 linesin the FUSE spectra and used to help analyze some features where blending withH2 was significant. The H I column density was determined from high resolutionHST/STIS spectra of Lyman alpha to be log(N HI) = 19.846+/-0.035 (2 sigma),which is higher than is typical for sight lines in the local ISM studied forD/H. We found that D/H =(1.39+/-0.21) E-5 (2 sigma) and O/H = (2.37+/-0.55) E-4(2 sigma). O/H toward BD +28 4211 appears to be significantly below the meanO/H ratio for the ISM and the Local Bubble.Comment: 33 pages, 12 figures, accepted for publication in The Astrophysical Journal Supplemen