Recent discovery of an Io-related feature in Jupiter's auroral regions prompted us to search for an or multiplet at 1304Å in IUE aurora spectra. In three independent IUE spectra taken on January 18, 1981, we found an emission structure at 1304Å , with a signal-to-noise of about three. If the structure is due to the OI emission, then it is a direct evidence of oxygen ion precipitation, which may originate from Io and Io torus. The emission rates of the H2 H2 band systems and the or multiplet are about 50 kR and 150 R, respectively. We have constructed high resolution model spectra with the estimated emission rates of H2 H2 , OI and SI for the Goddard High Resolution Spectrograph (GHRS) onboard the Hubble Space Telescope. The model spectra clearly show the or and SI mulitplets separated from crowded H2 H2 Lyman and Werner band lines, and therefore it is promising to detect the OI and SI multiplets with the GHRS. Given the possibility that the lo-related feature may be caused by ion precipitations from the Io flux tube, it is likely that the OI emission may be detected in the footprint area of the IO flux tube.

• Kim Sang-J.(Department of Astronomy and Space Science, Kyunghee University)
• Kim Yong-H.(Department of Astronomy and Space Science, Chungnam National University)