TY  - GEN
TI  - Be binary stars with hot, compact companions
Y1  - 2003///
AV  - public
ID  - heidok4343
KW  - Be-Stern 
KW  -  spektroskopischer Doppelstern 
KW  -  Be+sdO-Doppelstern 
KW  -  59 Cygni 
KW  -  phi PerseiBe star 
KW  -  spectroscopic binary 
KW  -  Be+sdO binary 
KW  -  59 Cygni 
KW  -  phi Persei
UR  - https://archiv.ub.uni-heidelberg.de/volltextserver/4343/
A1  - Maintz, Monika
N2  - In this study the importance of close binary evolution for Be star formation was investigated. The Be star 59 Cygni was confirmed to be an evolved binary with a sdO companion. The companion was confirmed by a weak helium II absorption. Orbital elements and stellar masses were determined. In the spectrum of 59 Cygni, characteristic features were identified. These are a single-peaked emission component, a phase-locked V/R variability, and a "knotty" structure of the absorption lines. According to Stefl et al. (2000), these features are caused by a hot, compact companion (sdO or WD) that photoionizes a sector of the disc of the Be star. Assuming this model and a code of Hummel and Stefl (2001) the emission variability of 59 Cygni was successfully reproduced. The features, observed in the spectrum of 59 Cygni, were confirmed for the Be+sdO binary phi Persei and for HR2142, too. Hence, these features were taken as indicators for Be binaries with hot, compact companions. HR2142 was confirmed to be a Be+sdO binary. The spectral variability of further candidates was examined. It was suggested that FY CMa is a Be+sdO binary and that kappa Draconis is a Be+WD binary. The assumption that a fraction of the Be stars formed by mass and angular momentum transfer in close binary systems was confirmed.
ER  -