FUSE Observations of the Halo Star HD 93521

FUSE spectra spanning 912Å - 1102Å have recently been obtained for the O star HD 93521. The position of this star in the halo (l=183, b=62, z ∼1.5 kpc) makes it ideal for gas abundance studies in an environment different from the Galactic disk or the local interstellar medium. This line of sight has been studied in detail by Spitzer and Fitzpatrick (1992, 1993), who determined column densities for low ionization species (including HI, SiII, SII, FeII, MgII, CaII) and the high ionization species SiIV and CIV. The low ionization species are distributed into 9 distinct velocity components that divide roughly into two groups: one at relatively low velocities and another at intermediate velocities ( ∼-60 km/s). The FUSE data provide complementary information for the important species DI, OI, NI, and ArI. We will present an analysis of the FUSE data on these species in the intermediate velocity gas.

Support for the FUSE mission is provided by NASA contract NAS5-32985.