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J.L. Linsky, B.E. Wood (JILA/Univ. Colo.), G. Hébrard, M. Lemoine, A. Vidal-Madjar (CNRS/IAP), K. Sembach (JHU), FUSE Science Team
We present and analyze spectra of the white dwarf WD1634-573 observed by the Far Ultraviolet Spectroscopic Explorer (FUSE) satellite. The spectra, observed through the large (LWRS) and medium (MDRS) apertures, contain absorption lines of many interstellar atoms and ions along the line of sight to the star. We fit profiles to lines of HI, DI, CII, CIII, NI, NII, OI, SiII, and ArI. When making these fits we solved for the column densities under a variety of assumptions concerning the interstellar medium including whether the local ISM has one or two velocity components and whether the temperatures, bulk velocities, and turbulent velocities are solved self-consistently or constrained to be typical values for the local ISM. We are able to fit the DI, NI, and OI column densities with relatively small uncertainties for this broad range of models. However the derived HI column density has large uncertainty due to the very saturated nature of the Lyman lines. We present accurate values of the D/O and D/N ratios from the FUSE data. At this time the HI column density is more accurately determined from EUVE spectra (Napiwotski et al 1996). We therefore use the HI column density obtained from EUVE data when determining D/H for this line of sight.
This work is based on data obtained for the Guaranteed Time Team by the NASA-CNES-CSA FUSE mission operated by the Johns Hopkins University. Financial support to U. S. participants has been provided by NASA contract NAS5-32985.
The author(s) of this abstract have provided an email address for comments about the abstract: jlinsky@jila.colorado.edu