A MINISURVEY OF INTERSTELLAR TITANIUM FROM THE SOUTHERN-HEMISPHERE

We describe the results of a minisurvey of interstellar Ti II and Ca I I absorption toward 42 early-type stars observed from the southern hem isphere at a spectral resolution of 4.5 km s(-1). Results are also pre sented for the Na I ultraviolet line (3302 Angstrom) detected toward n ine of these targets. We examine the dependence of the integrated colu mn densities of N(Ti II), N(Ca II), and N(Na I) on distance, reddening , neutral hydrogen column density, and their Galactic elemental abunda nce. Our findings support the proposition that Ti II and Ca II absorpt ion originates in the same regions of the pervasive, warm, and neutral intercloud gas of the interstellar medium. We have observed a correla tion of decreasing Ti and Ca abundance with increasing line-of-sight g as density. The Ti II/Ca II abundance ratio has been found to be essen tially constant under all the interstellar density conditions we have sampled. Thus, we conclude that the general absorption properties of t itanium (and calcium) are similar throughout the entire disk of our Ga laxy.