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Excitation rate coefficients and line ratios for the optical and ultraviolet transitions in S IINew calculations are reported for electron excitation collision strengths, rate coefficients, transition probabilities, and line ratios for the astrophysically important optical and UV lines in S II. The collision strengths are calculated in the close coupling approximation using the R-matrix method. The present calculations are more extensive than previous ones, including all transitions among the 12 lowest LS terms and the corresponding 28 fine-structure levels in the collisional-radiative model for S II. While the present rate coefficients for electron impact excitation are within 10-30 percent of the previous values for the low-lying optical transitions employed as density diagnostics of H II regions and nebulae, the excitation rates for the UV transitions 4S super 0 sub 3/2 - 4Psub 1/2,3/2,5/2 differ significantly from earlier calculations, by up to factor of 2. We describe temperature and density sensitive flux ratios for a number of UV lines. The present UV results are likely to be of interest in a more accurate interpretation of S II emission from the Io plasma torus in the magnetosphere of Jupiter, as well as other UV sources observed from the IUE, ASTRO 1, and the HST.
Document ID
19930071291
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Cai, Wei
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Pradhan, Anil K.
(Ohio State Univ. Columbus, United States)
Date Acquired
August 16, 2013
Publication Date
September 1, 1993
Publication Information
Publication: Astrophysical Journal Supplement Series
Volume: 88
Issue: 1
ISSN: 0067-0049
Subject Category
Astrophysics
Accession Number
93A55288
Funding Number(s)
CONTRACT_GRANT: NAG5-1644
CONTRACT_GRANT: NSF PHY-91-15057
Distribution Limits
Public
Copyright
Other

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