AAS 197, January 2001
Session 36. Deuterium Abundance in ISM: First {\it FUSE} Results
Display, Tuesday, January 9, 2001, 9:30am-7:00pm, Exhibit Hall

## [36.02] D/H Toward BD+28 4211: First FUSE Results

G. Sonneborn (NASA/GSFC), M. Andre, C. Oliveira, S.D. Friedman, J.C. Howk, J.W. Kruk, H.W. Moos, W.R. Oegerle, K.R. Sembach (JHU), P. Chayer (UVIC/JHU), T. Tripp, E.B. Jenkins (Princeton), G. Hebrard, A. Vidal-Madjar (CNRS/IAP), FUSE Science Team

The atomic deuterium-to-hydrogen abundance ratio has been evaluated for the sight line toward the hot O subdwarf BD+28\circ 4211. High signal-to-noise ratio (S/N~ 100) observations covering the wavelength range 905 - 1187 Å\ at a wavelength resolving power of \lambda/\Delta\lambda ~20,000 were obtained with the Far Ultraviolet Spectroscopic Explorer (FUSE) satellite. BD+28\circ 4211 is ~00 pc away with a total H I column density of ~ \times 1019 cm-2, much higher than is typically found in the Local ISM. The deuterium column density was measured by analyzing several D I Lyman series transitions (Lyman \delta, \epsilon, \eta, \theta, \iota) with curve of growth and profile fitting techniques, after determining which lines were free of interference from other interstellar species and narrow stellar features. The neutral hydrogen column density was measured by an analysis of the Lyman \alpha profile using HST/STIS and GHRS spectra. The stellar spectrum of BD+28\circ 4211 was modelled to assist in determining the sensitivity of H I (Ly \alpha) and D I to the continuum placement and to identify stellar transitions. The D I and H I column densities, their uncertainties, and potential sources of systematic error will be presented.

This work is based on data obtained for the FUSE 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 in part by NASA contract NAS5-32985.

The author(s) of this abstract have provided an email address for comments about the abstract: george.sonneborn@gsfc.nasa.gov