H
observations of the star FK Com
Department of Physics, Shoumen University, 9700 Shoumen, Bulgaria e-mail: [d.kyurkchieva;d.marchev]@shu-bg.net
Received:
14
June
2004
Accepted:
9
December
2004
High-resolution spectroscopic observations around the
Hα line of FK Com are presented. The analysis
of the spectra reveals that: (a) the intensity of the R peak of
the mean Hα profile is larger than that of the V peak;
(b) the intensities of the V and R emission peaks changes almost
in anti-phase; (c) the ratio 
varies in phase with V; (d) the
total Hα emission has a maximum at phase 0.75. The
similarity of the Hα profile of FK Com with those of the
disk-like stars leads us to the conclusion that its broad
two-peaked emission Hα line originates from an extended
disk. It is supposed that the disk produces the mean Hα
line. The variability of the Hα profile is explained by
the presence of additional sources of absorption and emission at
diametrically opposite regions of the disk. The asymmetry of the
mean Hα profile requires the disk to be
half-illuminated. It is supposed that a source of illumination is
a low-mass hot secondary orbiting the disk. A model of the
Hα emitting configuration of FK Com is proposed.
Key words: stars: activity / stars: binaries: spectroscopic / stars: chromospheres / stars: individual: FK Com
© ESO, 2005