Local Interstellar Medium Toward beta GEM and sigma GEM

Abstract

We present and analyze high-dispersion IUE observations of the interstellar magnesium, deuterium and hydrogen absorption profiles toward two late-type stars beta Gem (10.8 pc) and sigma Gem (59 pc) separated by 0.5 arcdeg on the sky. We confirm the velocity shift of the local interstellar cloud obtained for a bulk flow by Crutcher (1982). From the derived values of column densities of magnesium and deuterium we conclude that the LISM in that direction extends not further than about 10pc. We find the column density of deuterium equal to (4.7pm1.5)times10^{-13} cm^{-2} and an average HI density 0.075 cm}^{-3} leq n_HI leq 0.107 cm^{-3}. Abundance of the magnesium is about 1.1 dex smaller than the solar value.