Deuterium and Cosmology Research Programs

Deuterium is a relic of the primordial nucleosynthesis that occured between 100 and 1,000 seconds after the Big Bang. It is generally believed that since the Big Bang, deuterium has been destroyed but not created in nuclear reactions occuring inside of stars. We are analyzing Lyman resonance line absorption by interstellar deuterium and hydrogen seen in HST and FUSE spectra of nearby stars. The objective is to determine the D/H ratio and its possible variations in the interstellar gas clouds located in the disk of our Galaxy. The figure shows the D/H ratios that we have measured with HST spectra (diamonds) for lines of sight to nearby late-type stars as a function of distance to the star. Also plotted are D/H ratios obtained from FUSE spectra (squares) for stars both inside and outside the Local Bubble (log hydrogen column density < 19.2), from Copernicus (asterisks) and the IMAPS experiment (diamonds)..


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