We invite you to the public lecture in Astronomical
Institute,
Academy of Science of the Czech Republic
Monday January 10, 2005
13:00
in new lecture room in Astronomical Institute Ondrejov
An observational study of line-profile
variable B stars in multiple systems
Dr. Katrien Uytterhoeven
We present the results of the analysis of the pulsational
behaviour of the line-profile variable binary components of kappa
Scorpii, lambda Scorpii and epsilon Lupi.
Our research is situated in framework of a systematic long-term project
of line-profile variable B stars in close binary systems, with the aim
to search for tidally induced oscillations. Major unsolved questions in
the understanding of stars concern the role, if any, of binarity and
rotation on stellar pulsation-mode selection and on the enhancement of
pulsation-mode amplitudes.
We also studied the line-profile variations of the confirmed beta
Cephei stars kappa Scorpii and lambda Scorpii in detail in the broader
context of a seismic study. As the interior of stars is not directly
observable, accurate information is gathered from stellar
oscillations
which penetrate deep inside the star and whose behaviour is uniquely
determined by the properties of the overall stellar structure. It is of
utmost importance to identify with accuracy the pulsational frequencies
and wavenumbers of the pulsation modes.
High-resolution spectroscopy allows a detailed analysis of small
line-profile changes. Techniques have been proposed to disentangle
composite spectra, one of them being the KOREL code. It is unclear if
the line-profile variability is preserved well after disentangling. We
tested the performance of KOREL by means of the testcase kappa Scorpii.
Vladimir Karas
organizer
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