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Carbon and nitrogen abundances determined from transition layer linesThe possibility of determining relative carbon, nitrogen, and silicon abundances from the emission-line fluxes in the lower transition layers between stellar chromospheres and coronae is explored. Observations for main-sequence and luminosity class IV stars with presumably solar element abundances show that for the lower transition layers Em = BT sup -gamma. For a given carbon abundance the constants gamma and B in this relation can be determined from the C II and C IV emission-line fluxes. From the N V and S IV lines, the abundances of these elements relative to carbon can be determined from their surface emission-line fluxes. Ratios of N/C abundances determined in this way for some giants and supergiants agree within the limits of errors with those determined from molecular bands. For giants, an increase in the ratio of N/C at B-V of about 0.8 is found, as expected theoretically.
Document ID
19920052773
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Boehm-Vitense, Erika
(NASA Headquarters Washington, DC United States)
Mena-Werth, Jose
(Washington, University Seattle, United States)
Date Acquired
August 15, 2013
Publication Date
May 1, 1992
Publication Information
Publication: Astrophysical Journal, Part 1
Volume: 390
Issue: 1 Ma
ISSN: 0004-637X
Subject Category
Astrophysics
Accession Number
92A35397
Funding Number(s)
CONTRACT_GRANT: NAG5-1255
CONTRACT_GRANT: NGT-70006
CONTRACT_GRANT: NSG-5398
Distribution Limits
Public
Copyright
Other

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