Deuterium and Oxygen Toward Feige 100: Results from the Far Ultraviolet Spectroscopic Explorer (FUSE) Mission

We present measurements of the column densities of interstellar D I and O I made with the Far Ultraviolet Spectroscopic Explorer (FUSE), and of H I made with the International Ultraviolet ; 179_67 pc; z = Explorer (IUE) toward the sdOB star Feige 110 [(l,b) = (74?09, - 1_A+57_-227 pc]. Our determination of the D I column density made use of curve of growth fitting and profile fitting analyses, while our O I column density determination used only curve of growth techniques. The H I column density was estimated by fitting the damping wings of the interstellar Lya profile. We find log N(D I) = 15.47 + 0.06, log N(O I) = 16.73 + 0.10, and log N(H I) × 20.14_0.20+0.13(all errors 2a). This implies D/H (2.14 and O/H = (3.89 :k 1.67) FUSE results reported in companion papers (Moos et al. 2001) and previous measurements of the local interstellar medium, this suggests the possibility of spatial variability in D/H for sight lines exceeding _100 pc. This result may constrain models which characterize the mixing time and length scales of material in the local interstellar medium.