Discovery of a cataclysmic variable type companion of the M3 III giant 4 DRA with IUE.
Abstract
IUE observations show that the bright (mv∼5) normal M 3 III giant 4 Dra has a blue companion. Its spectrum increases to shorter wavelengths in the IUE short wavelength region and has strong emission lines of high excitation (CIV, NV, CIII, HeII, ...) superimposed. The spectrum of the companion of 4 Dra bears similarity to UV spectra of magnetic white dwarfs like AM Her and cataclysmic variables or old novae with some additional low excitation lines (CII, oI, . . .) possibly formed in the radiatively excited wind of the M giant. The spectrum of the 4 Dra companion is different from those of all other known WD companions of red giants (e.g. Mira, 56 Peg, SY For). 4 Dra is apparently member of a new subclass of interacting binary systems - a normal M giant plus an AM Her or cataclysmic variable type star.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- January 1985
- Bibcode:
- 1985A&A...142L..16R
- Keywords:
-
- Cataclysmic Variables;
- Companion Stars;
- Giant Stars;
- Spaceborne Astronomy;
- Emission Spectra;
- Iue;
- Stellar Mass Ejection;
- White Dwarf Stars;
- Astrophysics