Volume 371, Number 3, June I 2001
|Page(s)||1035 - 1047|
|Section||Interstellar and circumstellar matter|
|Published online||15 June 2001|
Line-profile variations of the double-lined spectroscopic binary Scorpii*
Instituut voor Sterrenkunde, Katholieke Universiteit Leuven, Celestijnenlaan 200 B, 3001 Leuven, Belgium
2 Netherlands Organisation for Scientific Research, Isaac Newton Group of Telescopes, Apartado 321, 38700 Santa Cruz de La Palma, Spain
3 Astronomical Institute Anton Pannekoek, University of Amsterdam, Kruislaan 403, 1098 SJ Amsterdam, The Netherlands
Corresponding author: K. Uytterhoeven, firstname.lastname@example.org
Accepted: 22 March 2001
We present a total time series of high signal-to-noise, high-resolution spectra of the SiIII , and Ålines of the fast-rotating, spectroscopic binary and β Cephei star κ Scorpii. Among this data set is a sample of 422 spectra of intensive monitoring during eight subsequent nights in July 1997. We find variability of the line profiles on two time-scales: a variation of several months as a result of the orbital motion and rapid variations of a few hours, which are explained in terms of non-radial pulsation modes. From the total dataset, covering a time span of 9 years, we derive for the first time the orbital parameters of κ Scorpii and find an orbital period of 195 days. The complex patterns on the grayscale representations of the residual SiIII Åprofiles with respect to the average profile point towards more than one (non-axisymmetric) pulsation mode. A frequency analysis of the three normalised velocity moments confirms the main period of 4.80 hours and the second period of 4.93 hours, which were previously derived from photometric data. We attempt an identification of the pulsation modes by means of the moment method and line-profile fitting and find that κ Scorpii pulsates in a main prograde sectoral mode of degree 1 or 2 and in an additional tesseral mode for which , are the most likely wavenumbers. In the variations of the line profiles we find indications for the presence of additional pulsation modes.
Key words: stars: binaries: spectroscopic / stars : oscillations / line: profiles / stars: individual: κ Scorpii
© ESO, 2001
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