[Previous] | [Session 18] | [Next]
J. Gustin (LPAP, Université de Liège, Belgium), P.D. Feldman (Johns Hopkins University, Baltimore), J-C. Gérard (LPAP, Université de Liège, Belgium), L. Ben-Jaffel, J-M. Desert (IAP, France), H.W. Moos, D.J. Sahnow, H.A. Weaver, B.C. Wolven (Johns Hopkins University, Baltimore), E. Roueff, H. Abgrall (Observatoire de Paris, France), J. Ajello (Jet Propulsion Laboratory, Pasadena), A. Vidal-Madjar (IAP, France)
High-resolution spectra of the Jovian aurora have been obtained with unprecedented spectral resolution in the 900-1190 Åwindow with the the Far Ultraviolet Spectroscopic Explorer (FUSE), using the 30"x30" LWRS aperture. All observed features belong to the H2 transitions from the B, C, B', D, B" and D' electronic states to the ground-state. These emissions are excited by inelastic collisions of the primary and secondary auroral electrons with H2 molecules. The relative intensity distribution of the observed lines depends on the rotational temperature of the emitting layer and self-absorption. Below 1100 Å, the transitions leading to the v" = 0, 1 and 2 levels of ground-state are partially or totally absorbed by H2, giving indications about the vibrational H2 distribution and overlying column.
After a validation with an unabsorbed and a self-absorbed laboratory spectrum obtained in controlled conditions (100K, 300 eV), this study compares the observations and synthetic spectra, generated by a code including the B, C and B', D, B" and D' Rydberg states. The rotational and vibrational H2 temperatures are determined as well as the overlying H2 column. The combination of these parameters is used to determine the depth of the auroral energy deposition.
This work is based on data obtained for the Guaranteed Time Team by the NASA-CNES-CSA FUSE mission operated by the Johns Hopkins University. French participants are supported by CNES. Financial support to U.S. participants has been provided by NASA contract NAS5-32985.