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Astron. Astrophys. 346, 520-522 (1999)
On the determination of carbon isotopic ratios in cool carbon stars
II. Accuracy of the iso-intensity method for crowded spectra
P. de Laverny 1 and
B. Gustafsson 2
1 Observatoire de la Côte d'Azur, Département Fresnel UMR 6528, B.P. 4229, F-06304 Nice, France
2 Astronomiska Observatoriet, Box 515, S-751 20 Uppsala, Sweden
Received 5 March 1999 / Accepted 26 March 1999
Abstract
de Laverny & Gustafsson (1998, Paper I) questioned the iso-intensity method used by Ohnaka & Tsuji (1996) to derive carbon isotopic ratios in cool carbon stars. As a reply, Ohnaka & Tsuji (1998) pointed out that the method criticized in Paper I differs from the original one and conclude that our results are unreliable. No comparison of the two methods was, however, made. The iso-intensity method used in Paper I and OT96 do slighty differ in their definition. In investigating the consequences of this difference we have found that they are rather insignificant. We therefore confirm that the iso-intensity method is not reliable when applied to crowded spectra of cool stars. That reinforces the conclusions presented in Paper I.
Key words: stars:
abundances 
stars:
late-type
stars: AGB and
post-AGB
stars: carbon
molecular processes
Send offprint requests to: P. de Laverny (laverny@obs-nice.fr)
This article contains no SIMBAD objects.
Contents
- 1. Introduction
- 2. Comparison of the iso-intensity methods of Paper I and OT96.
- 3. Conclusion
- Acknowledgements
- References
© European Southern Observatory (ESO) 1999
Online publication: May 21, 1999
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