The ORFEUS II Echelle Spectrum of HD 93521: A reference for interstellar molecular hydrogen

Abstract

During the second flight of the ORFEUS-SPAS mission in November/December 1996, the Echelle spectrometer was used extensively by the Principal and Guest Investigator teams as one of the two focal plane instruments of the ORFEUS telescope. The spectrum of HD 93521 was obtained during this mission with a total integration time of 1740 s. This spectrum shows numerous sharp interstellar absorption lines. We identified 198 lines of molecular hydrogen including at least 7 lines with a high velocity component. Also most of the 67 identified interstellar metal lines are visible with a high velocity component. We present plots of the complete ORFEUS Echelle spectrum together with tables of all identified interstellar absorption lines including all 14 detectable HI lines. In addition several identified stellar lines, partially with narrow absorption components, and stellar wind lines are given in a separate table.