http://www.vilspa.esa.es/sl9/walt_harris_report.html (Einblicke ins Internet, 10/1995)

Report from Walt Harris (IUE US science team ) 21 July 1994

Report from Walt Harris (IUE US science team ) 21 July 1994.

Observations of the Jupiter system have been performed with the IUE satellite on a 24 hour basis since the 15th of July, and intermittantly since early June. The IUE imaging spectrographs have a combined spectral coverage from 1150-3300A at resolutions from .14 to 6A. We are monitoring several of the best studied upper atmospheric features of Jupiter and its magnetosphere including the Aurora, the LY-a equatorial anomaly, and the Io torus. We have detected changes in some of these features (in particular, the aurora has been weak) that we attribute to (or at least find suspiciously coincidental with) the effects of the comet fragment impacts and/or to the passage of dust through the inner Jovian magnetosphere.

The IUE is also being used to monitor the development of spectral features in the impact areas, and in particular has been useful for showing the timescales that describe the development of the dark features seen in the WFPC-II images. The A, B, E, G, K, and Q impacts have been observed wiht great success. For instance, our analysis of spectra obtained on the approaching and receeding limb while we followed the G impact site with the IUE small aperture show that the region experienced a 50% drop in reflectivity as it rotated moved across the disk of the planet. Many possible absorption and emission features have also been observed in spectra obtained from the impact sites. We have not as yet had an opportunity to analyze these features properly.

We are also performing an unprecedented number of simultaneous observations with other instruments. This is providing new insight into the characteristics of features long studied with the IUE, and gives the operators of the other instruments an opportunity to compare the results of their observations with the more than 15 years of Jovian FUV spectra in the archives.

Along with our European collaborators, we will continue to monitor the effects of the impacts on a 24 hour basis with the IUE until the end of the week, and then on a less regular schedule until it becomse unobservable with the satellite on Aug. 15.

Walt Harris; for the IUE US science team 7/21/94