Deuterium and Oxygen toward Feige 110: Results from the FUSE Mission
Sembach, K. R.; Sonneborn, G.; Moos, H. W.; André, M.; Chayer, P.; Vidal-Madjar, A.; Hébrard, G.; Friedman, S. D.; Jenkins, E. B.; Oegerle, W. R.; Tripp, T. M.; Howk, J. C.; Lamontagne, R.; Oliveira, C.
United States, Canada, France
Abstract
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 Explorer (IUE) toward the sdOB star Feige 110 [(l,b)=(74.09d,-59.07d) d=179+265-67 pc; z=-154+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 Lyα profile. We find logN(DI)=15.47+/-0.06, logN(OI)=16.73+/-0.10, and logN(HI)=20.14+0.13-0.20 (all errors 2 σ). This implies D/H=(2.14+/-0.82)×10-5, D/O=(5.50+1.64-1.33)×10-2, and O/H=(3.89+/-1.67)×10-4. Taken with the FUSE results reported in companion papers and previous measurements of the local interstellar medium (LISM), 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 timescales and length scales of material in the LISM.