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A Minor Outburst during the Quiescent Period of the Symbiotic Star Ch-Cygni
Hack, Margherita; Aydin, Cemal
We have studied a few optical spectra of the symbiotic star CH Cygni obtained in the period January 1990-June 1991, which indicate that a mild increase of activity occurred between July and December 1990. This increase of activity is confirmed by the IUE observations made in the same period. In fact, in this period of time, we have observed an inc…
Detection of Rs-Canum Type Systems by Doublet 2800 MGII
Gurzadian, G. A.; Cholakian, V. G.
The problem of the detection or discovery of RS CVn-type close binary systems with the aid of the magnesium emission doublet 2800 MgII is discussed. On the example of a star, HD 102077, the possibility of such an approach is shown. The determining factor is the magnitude of the measureless parameterR(MgII), that is, the relative power of the magne…
Stellar Wind Velocities and the Radiation-Driven Winds Theory for O-Stars
Bernabeu, G.
In this paper we have carried out an analysis of the predictions of the radiatively driven stellar winds theories on 63 stars belonging to clusters or associations. The spectral types in our sample range from O3 to B0 and all classes of luminosity are considered. The study has been carried out starting from the relationship between the stellar-win…
The Ultraviolet Spectrum of the Binary System Sz-Piscium
Mathioudakis, M.; Danezis, E.; Theodossiou, E. +1 more
In this paper we study the far-UV as well as the UV spectrum of the spectroscopic binary system SZ Psc in the wavelength ranges λλ1235–1950 Å and λλ2710–3090 Å, respectively, from spectra obtained with the International Ultraviolet Explorer (IUE). The UV spectrum of SZ Psc is mainly an emission spectrum. The short wavelength region includes emissi…
X-ray VS He ii λ1640 Å correlation of II Peg
Esendemir, A.; Alev, H. M.
The HeII λ1640 Å emission feature on the IUE spectra of II Peg has been compared with the observed X-ray flux. The atmospheric activity level is determined by comparing the several diagnostic line intensities with the solar case.