Interstellar Deuterium Abundance in the Direction of Beta Centauri

Abstract

Interstellar absorption lines due to the Lyman series transitions in hydrogen and deuterium have been observed in the spectrum of Cen. From these, a ratio oi deuterium to hydrogen, by number, of 1.4 0.2 (m.e.) >c 10- has been obtained. If one assumes that the present deuterium abundance is a relic of the big-bang element synthesis, a value of 1.5 X 10-31 g cm-3 for the present density of the Universe is derived. Subject headings:abundances - cosmology - interstellar matter - spectra, ultraviolet