D/H as a Measure of Chemical Imhomogeneity in our Galaxy

Abstract

Accurate measurements of interstellar deuterium abundances along lines of sight extending out to several hundred parsecs by FUSE and other instruments is making D/H a useful tool for understanding Galactic chemical evolution. We find that the gas inside of the Local Bubble is chemically homogeneous, but that large variations in D/H beyond the Local Bubble are real and challenge present concepts of chemical evolution. A new set of models is needed that will include spatially dependent infall of relatively unprocessed material, depletion of D onto grains, and appropriate mixing timescales. $

10 pages, 1 figure, to be published in Carnegie Observatories Astrophysics Series, Vol 4 Origin and Evolution of the Elements, 2003