EUVE Observations of the Io Plasma Torus

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Session 25 -- EUVE -- Astronomy I
Oral presentation, Tuesday, 8:30-12:30, Zellerbach Auditorium Room

[25.08] EUVE Observations of the Io Plasma Torus

H.W.Moos, D.T.Hall, P.D.Feldman, D.F.Strobel (Johns Hopkins Univ), M.A.McGrath (STScI), J.T.Clarke (Univ of Mich), J.H.Waite (SW Res Inst), G.R.Gladstone (UC Berkeley), F.Bagenal, N.M.Schneider (Univ of Colo), D.E.Shemansky (USC)

The first observation of Jupiter using the Long Wavelength detector of the Extreme Ultraviolet Explorer satellite shows a rich emission spectrum from the Io plasma torus. At least 12~features between 350~and 750~\AA\ are apparent in the 59,000~second exposure obtained on March~30 and April~1,~1993. Several lie below the short wavelength cutoff of the Voyager spacecraft~UV instruments, and have not been observed previously. Preliminary analysis of the raw detector image identifies most of the features as multiplets of oxygen and sulfur ions. The emissions are spatially resolved along the long dimension of Io's projected orbital ellipse, with the brightest located approximately at each ansa of Io's orbit. Most of the ansa emissions show a distinct dawn/dusk asymmetry.

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