D/O and D/N towards HZ 43: First FUSE Results
Abstract
High resolution spectra of the DA white dwarf HZ 43 covering the wavelength range 905--1187Å were obtained with the Far Ultraviolet Spectroscopic Explorer (FUSE) for the purpose of studying the deuterium abundance of the local interstellar medium. These spectra exhibit clean interstellar lines of O i and N i, permitting a determination of the column densities for these species. Only an upper limit to the D i absorption could be determined, because of contamination by the H i geocoronal airglow admitted by the large aperture used for this observation. Archival HST/GHRS spectra in the vicinity of Lyman α were used instead to determine the D i and H i column densities, the latter determined from a fit to the damping wings of the Lyman α transition. Further FUSE observations of HZ 43 using the smaller MDRS aperture will be obtained in order to better constrain the D i column density using the Lyman-series lines in the FUSE bandpass. We will present determinations of the column densities and uncertainties of interstellar D i, H i, O i, and N i along this sight line and discuss the potential sources of systematic error in these measurements. 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.
- Publication:
-
American Astronomical Society Meeting Abstracts
- Pub Date:
- December 2000
- Bibcode:
- 2000AAS...197.3606K