Composition of interstellar clouds in the disk and halo. I - HD 93521
L. Spitzer, E. L. Fitzpatrick;
ApJ, 1993, 409, 299
ABSTRACT:Interstellar column densities of Fe, S, Si, Mn, and Mg in their dominant ionization state, as well as of C(+) and S(2+), are presently derived from analyses
of HST UV observations of the Galactic halo star HD 93521.
Ratios of
column densities for the dominant species yield approximations of the
logarithmic depletion D(X) in the warm, primarily neutral H gas which produces each
of the resolved components.
Variations of D between components are
highly correlated between elements; about two Fe atoms leave the grains for
every Si atom, as if these atoms were primarily bound in the Fe2SiO4 molecules
within the grain cores.
KEYWORDS: chemical composition, electron density profiles, galactic halos, interstellar gas, ultraviolet astronomy, atomic excitations, hubble space telescope, line of sight, milky way galaxy
PERSOKEY:absorption, hst, h_i, h+, uv, ,
CODE: spitzer93