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| Paper: |
A Method of Measuring Gamma-Velocities of Contact Binary Stars |
| Volume: |
185, Precise Stellar Radial Velocities, IAU Colloquium 170 |
| Page: |
321 |
| Authors: |
Kaszás, G.; Vinkó, J.; Fürész, G. |
| Abstract: |
We have studied the radial velocities of some of the brightest, northern contact binary stars using medium-resolution spectra (R = 11,000) obtained with the Cassegrain spectrograph attached to the 74'' telescope of David Dunlap Observatory (Toronto, Canada). The spectra covered the 6500 - 6700 Å wavelength interval including the Hα region. The spectra were reduced with standard IRAF routines including bias correction, flat fielding, cosmic ray removal and continuum normalization. Telluric lines were removed using observed telluric standard stars. The radial γ -velocities of these binary systems were derived by cross-correlating the contact binary spectra with synthesized model line profiles computed by a newly developed computer code. Our tests showed that this method has internal accuracy of better than 2 km/s whereas the broadening caused by the orbital motion is larger than 200 km/s in most cases. We conclude that the gamma -velocities obtained with our method are adequate and useful to investigate the kinematic properties of WUMa-type binary stars. The kinematics of these stars may contain important information on their galactic population and evolutionary state which is still an unsolved mystery of binary star astrophysics. |
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