SVIBOR - Project code: 1-04-157


Strossmayerov trg 4, HR - 10000 ZAGREB
tel.: +385 1 459 44 44, fax: +385 1 459 44 69


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Project code: 1-04-157

Symbiotic stars and atmospheric eclipsing binaries

Main researcher: KOTNIK-KARUZA, DUBRAVKA (48086)

Type of research: basic
Duration from: 01/01/91. to 12/31/93.

Papers on project (total): 23
Papers on project quoted in Current Contents: 2
Institution name: Pedagoški fakultet, Rijeka (9)
Department/Institute: Physics department, Faculty of education, University of Rijeka
Address: Omladinska 14, 51000 Rijeka
City: 51000 - Rijeka, Croatia
Phone: 385 (0) 51 516322
Fax: 385 (0) 51 515142
Phone: 385 (0) 51 227474
Phone: 385 (0) 51 516322,227474

Summary: Systematic observation and spectral analysis of symbiotic stars for long periods of time in the optical and ultraviolet spectral region help in understanding the reason of their variability and outbursts at irregular time intervals.The results of the measurements of radial velocities,line profiles and line intensities can be used to construct theoretical models in order to explain the physical phenomena which are the origin of the observed variability. The symbiotic star CH Cygni has been taken as a representative in such investigations. We have analysed the high resolution spectra taken at the French National Observatory in Haute Provence and reduced using the programs avaliable at the ASTRONET pole of Trieste. The observations which extend over the last quiescent period of the star are of great interest since they are unique and unrepeatable and therefore important to understand the behaviour of such unpredictable objects. Besides, this quiescent phase appears to be short and the previous interoutburst periods have not been investigated. Our spectroscopic studies lead to a more complete radial velocity curve and confirm the binary model of this symbiotic variable. The monitoring of the time development of some physical parameters, line profiles and molecular bands in the quiescent phase lead to the explanation of the atmospheric structure and processes during this period as well as to the discovery of the signs of a new outburst.

Keywords: Symbiotic stars,,CHCygni,quiescence,optical spectrum, physical parameters

Research goals: The aim of this research was to continue the observations of the symbiotic star CH Cygni in order to understand the reasons of its variability and outbursts as well as to derive reliable orbital data and theoretical model. This star has been observed systematically since 1965. in the optical and since 1978. also in the ultraviolet spectral region. Three outbursts have been recorded at irregular time intervals with a pronounced symbiotic character of the spectrum, while the interoutburst intervals have not been investigated. This work deals with one of the quiescent phases of the star in the period 1987-1989 which follows the longest spectroscopically observed activity phase. The optical spectra have been analysed in order to establish the structure and processes in the stellar atmosphere and to reveal the signs and possible reason of outbursts. Besides, extending the observations over a larger period provides more data for building a suitable model of the star and to derive reliable orbital parameters.


  1. Name of institution: Universita degli Studi di Trieste Dipartimento di Astronomia Trieste Italia
    Type of institution: University/Faculty
    Type of cooperation: Systematic exchange of information
    City: 34131 - Trst (I), Italija

  2. Name of institution: Opservatorij Hvar Geodetskog fakulteta u Zagrebu
    Type of institution: University/Faculty
    Type of cooperation: Occasional exchange of information
    City: 10000 - Zagreb, Croatia

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Last update: 12/21/95