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Astron. Astrophys. 333, 658-664 (1998)


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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

© European Southern Observatory (ESO) 1998

Online publication: April 20, 1998
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