Deuterium and Oxygen Toward Feige 110: Results from the Far Ultraviolet Spectroscopic Explorer (FUSE) Mission

摘要

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) = (74.09 deg., - 59.07 deg.); d = 179(sup 265, sub -67) pc; Z = -154(sup 57, Sub -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 Ly(lpha) 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(sup 0.13, sub -0.20) (all errors 2(sigma)). This implies D/H = (2.14 /- 0.82) x 10(esp -5), D/O = (5.50(sup 1.64, sub -133)) x 10(exp -2), and O/H = (3.89 /- 1.67) x 10(exp -4). Taken with the FUSE results reported in companion papers and previous measurements of the local interstellar medium, this suggests the possibility of spatial variability in D/H for sight lines exceeding approx. 100 pc. This result may constrain models which characterize the mixing time and length scales of material in the local interstellar medium.