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Fe II emission lines. I - Chromospheric spectra of red giantsA 'difference filtering' algorithm developed by Ayers (1979) is used to construct high-quality high-dispersion long-wavelength IUE spectra of three giant stars. Measurements of all the emission lines seen between 2230 and 3100 A are tabulated. The emission spectrum of Fe II is discussed in comparison with other lines whose formation mechanisms are well understood. Systematic changes in the Fe II spectrum are related to the different physical conditions in the three stars, and examples are given of line profiles and ratios which can be used to determine conditions in the outer atomspheres of giants. It is concluded that most of the Fe II emission results from collisional excitation and/or absorption of photospheric photons at optical wavelengths, but some lines are formed by fluorescence, being photoexcited by other strong chromospheric lines. Between 10 and 20 percent of the radiative losses of Fe II arise from 10 eV levels radiatively excited by the strong chromospheric H Ly-alpha line.
Document ID
19910066714
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Judge, P. G.
(Joint Institute for Laboratory Astrophysics Boulder, CO, United States)
Jordan, C.
(Oxford, University United Kingdom)
Date Acquired
August 14, 2013
Publication Date
September 1, 1991
Publication Information
Publication: Astrophysical Journal Supplement Series
Volume: 77
ISSN: 0067-0049
Subject Category
Astrophysics
Accession Number
91A51337
Funding Number(s)
CONTRACT_GRANT: NAS5-28731
CONTRACT_GRANT: NAG5-1306
Distribution Limits
Public
Copyright
Other

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