The Deuterium, Oxygen, and Nitrogen Abundance Toward LSE 44

We present measurements of the column densities of interstellar DI and OI made with the Far Ultraviolet Spectroscopic Explorer (FUSE), and of HI made with the International Ultraviolet Explorer (IUE) toward the sdOB star Feige 110 [(l,b) = (74.09, -59.07); d = 179 +265 -67 pc; z = -154 +57 -227 pc]. Our determination of the DI column density made use of curve of growth fitting and profile fitting analyses, while our OI column density determination used only curve of growth te...

We use new FUSE data to determine the column densities of interstellar DI, NI, OI, FeII, and H2 along the HD41161 and HD53975 sightlines. Together with N(HI) from the literature (derived from Copernicus and IUE data) we derive D/H, N/H, and O/H ratios. These high column density sightlines have both log H(HI)>21.00 and allow us to probe gas up to 1300 pc. In particular these sightlines allow us to determine the gas phase D/H ratio in a hydrogen column density range, log N(H)>2...

We use high resolution spectra obtained with FUSE and STIS to obtain interstellar column densities of H I, D I, O I, S II, Fe II and P II toward the QSO HE 0226-4110 ( l = 253.4 deg , b = -65.77 deg). We obtain D/H = 21(+8, -6) ppm. Correcting for a small amount of contamination from D and H in the Local Bubble, we obtain D/H = 22 (+8, -6) for the warm neutral medium of the lower Galactic halo. The medium has [O/H] = 0.12(+0.41, -0.20) and [Fe/H] = -1.01 (+0.10, -0.09). This ...

The first observations of deuterium and oxygen in the Local Interstellar Medium (LISM) obtained with the Far Ultraviolet Spectroscopic Explorer (FUSE) can be used to search for local abundance variations. While the very limited sample of these first data may be consistent with no variations, they do offer a hint of anti-correlated variations between D/H and O/H. If confirmed by more data (which will require independently determined, accurate HI column densities), these hints ...

An accurate value of the deuterium/hydrogen (D/H) ratio in the local interstellar medium (LISM) and a better understanding of the D/H variations with position in the Galactic disk can provide essential information on the primordial D/H ratio in the Galaxy at the time of the protosolar nebula, and the amount of astration and mixing in the Galaxy over time. Recent measurements have been obtained with UV spectrographs on FUSE, HST, and IMAPS using hot white dwarfs, OB stars, and...

High-resolution spectra of the hot white dwarf G191-B2B, covering the wavelength region 905-1187A, were obtained with the Far Ultraviolet Spectroscopic Explorer (FUSE). This data was used in conjunction with existing high-resolution Hubble Space Telescope STIS observations to evaluate the total HI, DI, OI and NI column densities along the line of sight. Previous determinations of N(DI) based upon GHRS and STIS observations were controversial due to the saturated strength of t...

We present a deuterium abundance analysis of the line of sight toward the white dwarf WD2211-495 observed with the Far Ultraviolet Spectroscopic Explorer (FUSE). Numerous interstellar lines are detected on the continuum of the stellar spectrum. A thorough analysis was performed through the simultaneous fit of interstellar absorption lines detected in the four FUSE channels of multiple observations with different slits. We excluded all saturated lines in order to reduce possib...

Accurate measurements of interstellar deuterium abundances along lines of sight extending out to several hundred parsecs by FUSE and other instruments is making D/H a useful tool for understanding Galactic chemical evolution. We find that the gas inside of the Local Bubble is chemically homogeneous, but that large variations in D/H beyond the Local Bubble are real and challenge present concepts of chemical evolution. A new set of models is needed that will include spatially d...

We present new measurements of the oxygen gas-phase abundance along four sightlines probing gas inside the Local Bubble, using data obtained with the Far Ultraviolet Spectroscopic Explorer (FUSE) and the Hubble Space Telecope (HST). Combining these with seven previously published N(O I) and N(H I) measurements we determine a mean O/H ratio for the Local Bubble, (O/H) = (3.45 +/- 0.19)x10^(-4) (1 sigma in the mean). Our result is virtually identical to O/H = (3.43 +/- 0.15)x10...

We present a measurement of the D/H abundance ratio in a metal-poor damped Lyman alpha (DLA) system along the sightline of QSO SDSS1558-0031. The DLA system is at redshift z = 2.70262, has a neutral column density of log(NHI)=20.67+/-0.05 cm^2, and a gas-phase metallicity [O/H]= -1.49 which indicates that deuterium astration is negligible. Deuterium absorption is observed in multiple Lyman series with a column density of log(NDI)=16.19+/-0.04 cm^2, best constrained by the deu...