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Astron. Astrophys. 333, 658-664 (1998)
Spectroscopic observations of D-type symbiotic stars * **
C.B. Pereira ,
S.J.C. Landaberry and
S. Junqueira
Observatório Nacional, Departamento de Astronomia
Galáctica e Extra-Galáctica, Rua José Cristino,
77, CEP 20921-400, São Cristóvão, Rio de
Janeiro-RJ, Brazil
Received 15 October 1997 / Accepted 14 January 1998
Abstract
Observations of five D-type symbiotics are presented: three oxygen Mira (He2-38, H2-38 and H1-36) and two carbon Mira symbiotics (AS 210 and SS 38). The observations in the spectral range between 3200Å and 7400Å show the presence of several emission lines in various states of excitation. A line list is provided with their suggested identifications. Several parameters were derived for each object: interstellar reddening as determined from Balmer decrement and He II lines, temperature and electronic density, abundance ratios of Ne/O, Ar/O, Fe/Ne, N/O and He/H. We found nitrogen enrichment while for the other elements their abundances are compatible with solar, except iron which is depleted. We did not detect significant changes in the line and in the continuos spectra of the stars analyzed here, except for He2-38, which increased its degree of excitation compared to Allen's (1984) catalogue.
Key words: stars:
abundances 
binaries: symbiotic
* Based on observations made with the 1.52m telescope at the European Southern Observatory (La Silla, Chile) under the agreement with the CNPq-Observatório Nacional (Brazil)
** Table 7 is only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/Abstract.html
Send offprint requests to: C.B. Pereira
Contents
- 1. Introduction
- 2. Observations and reductions
- 3. The spectra
- 4. Extinction
- 5. Physical conditions
- 6. Abundances
- 6.1. Helium abundances
- 7. Conclusions
- Acknowledgements
- References
© European Southern Observatory (ESO) 1998
Online publication: April 20, 1998
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