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Hopkins Ultraviolet Telescope determination of the Io torus electron temperatureSulfur ion emissions from the Io plasma torus observed by the Hopkins Ultraviolet Telescope (HUT) in 1990 December have been analyzed to determine the effective temperature of the exciting electrons. Spectra were obtained with a long slit that extended from 3.1 to 8.7 Jupiter radii R(sub J) on both dawn and dusk torus ansae. The average temperature of electrons exciting S(2+) emissions from the dawn ansa is (4800 +/- 2400) K lower than on the dusk ansa, a dawn-dusk asymmetry comparable in both sign and magnitude to that measured by the Voyager Ultraviolet Spectrograph (UVS) experiment. Emissions from S(2+) ions are generated in a source region with electron temperatures in the range 32,000-56,000 K; S(3+) ion emissions are excited by electrons that average 20,000-40,000 K hotter. This distinct difference suggests that the S(3+) emission source region is spatially separate from the S(2+) source region. Estimated relative aperture filling factors suggest that the S(3+) emissions originate from a region more extended out of the centrifugal plane than the S(2+) emissions.
Document ID
19950037955
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Hall, D. T.
(Johns Hopkins Univ. Baltimore, MD, United States)
Bednar, C. J.
(Johns Hopkins Univ. Baltimore, MD, United States)
Durrance, S. T.
(Johns Hopkins Univ. Baltimore, MD, United States)
Feldman, P. D.
(Johns Hopkins Univ. Baltimore, MD, United States)
Mcgrath, M. A.
(Space Telescope Science Inst. Baltimore, MD, United States)
Moos, H. W.
(Johns Hopkins Univ. Baltimore, MD, United States)
Strobel, D. F.
(Johns Hopkins Univ. Baltimore, MD, United States)
Date Acquired
August 16, 2013
Publication Date
January 1, 1994
Publication Information
Publication: Astrophysical Journal, Part 2 - Letters
Volume: 420
Issue: 1
ISSN: 0004-637X
Subject Category
Astronomy
Accession Number
95A69554
Funding Number(s)
CONTRACT_GRANT: NAG5-2390
CONTRACT_GRANT: NAS5-27000
Distribution Limits
Public
Copyright
Other

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