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Title: Finding that almos two-thirds of contact binaries are members of multiple stellar systems.
Authors: T. Pribulla, S.M. Rucinski
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Description: Contact binary stars are systems with the lowest angular momentum among close binaries with non-degenerate components. Therefore, their origin requires substantial angular momentum loses. The present study of multiplicity of contact binaries uses all available observations such as: high-dispersion spectroscopy, direct observations using speckle interferometry and adaptive optics, astrometric observations (parallax and proper-motion errors), spectral-energy-distribution peculiarity (including x-ray radiation), so-called light-time effect caused by the finite speed of light, binary orbit precession etc. Several techniques were combined for individual objects. The final result is that in the sample of 138 contact binaries (brighter that V=10 in the maximum) the lower limit of the multiple stellar systems incidence is 42±5%, while in the much better studied Northern-hemisphere sample it is as much as 56±8%. Adding all suspicious cases for northern objects would increase the incidence to 68±9%. The detected high incidence of multiplicity supports the hypothesis that all contact binaries were formed in the multiple systems.
Reference: Astronomical Journal 131, 2986–3307 (2006).
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Date and Time: 14.12. 2017 14:19:07 CET
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