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		| Paper: | 
		Binaries in the Hipparcos Data:  Keep Digging, I. Search for Binaries Without 'a priori' Knowledge of Their Orbital Elements:  Applications to the Barium Stars | 
	 
	
		| Volume: | 
		318, Spectroscopically and Spatially Resolving the Components of Close Binary Stars | 
	 
	
		| Page: | 
		141 | 
	 
	
		| Authors: | 
		Jorissen, A.; Jancart, S.; Pourbaix, D. | 
	 
	
	
		| Abstract: | 
		This work makes use of Hipparcos data to test the algorithms of (i) binary detection and (ii) orbital-parameters determination, which could possibly be used in the GAIA pipeline. The first item is addressed in this paper, whereas the second one is addressed in a companion paper by Pourbaix, Jancart, & Jorissen (2004, this volume). Here we test the ability of the algorithm to detect binaries from scratch, i.e., from the astrometric data without any a priori knowledge of the orbital elements. The Hipparcos Intermediate Astrometric Data of a complete sample of 163 barium stars (supposed to be all members of binary systems from theoretical considerations) are used as a test bench. When ω > 5 mas and Ρ < 4000 d, the binary detection rate is close to 100%, but it falls to 22% when considering the whole sample, because many barium stars have small parallaxes or very long periods. | 
	 
	
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