2001ApJ...558..133M

We discuss the interstellar absorption lines found in Far Ultraviolet Spectroscopic Explorer spectra of the Wolf-Rayet binary Sk 108, which is located in the northeastern part of the main ``bar'' of the Small Magellanic Cloud. The spectra cover the 988-1187 Å wavelength range at a resolution of about 12,000 and a signal-to-noise ratio of 20-40. We use detailed component information from higher resolution near-UV and optical spectra to model the far-UV lines of similarly distributed species. Both the Galactic and SMC gas toward Sk 108 seem to be predominantly neutral, although a significant fraction of the SMC gas is ionized. The column densities of P II, S II, and Ar I are consistent with essentially solar ratios, relative to N(Zn II), in both the Galactic and SMC gas; the column density of N I remains somewhat uncertain. Molecular hydrogen is present in the Galactic gas, with properties similar to those found in low mean density Galactic lines of sight and in the Galactic gas toward several other LMC and SMC stars. We report a tentative detection of H₂ in the SMC gas for J=1 and 3, with rotational level populations consistent with an excitation temperature on the order of 1000 K–similar to the H₂ found in diffuse Galactic gas toward ζ Puppis. Strong absorption from N III, S III, and Fe III has revealed a significant ionized component, particularly in the SMC; O VI is present, but relatively weak, especially in the Galactic gas. The N(C IV)/N(O VI) ratio varies somewhat within the SMC, suggesting that several processes may contribute to the observed high ion abundances.