ORFEUS-II-ECHELLE SPECTRA - DETECTION OF H-2 ABSORPTION IN SMC GAS

We present a study of H-2 in the SMC gas, based on Far UV spectroscopy in the line of sight to the SMC star HD 5980. 17 absorption lines fro m the Lyman band have been analysed. Our line of sight crosses two clo uds within the SMC. We detect a cool molecular component near +120 km s(-1), where the Hz from the lowest 3 rotational states (J less than o r equal to 2) is found. For this cloud we derive an excitation tempera ture of similar or equal to 70 K, probably the kinetic temperature of the gas. Another SMC component is visible at +160 km s(-1). Here we fi nd unblended H-2 absorption lines from levels 5 less than or equal to J less than or equal to 7. For this component we obtain an equivalent excitation temperature of >2350 K and conclude that this cloud must be highly excited by strong UV radiation from its energetic environment.