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		| Paper: | 
		Studies of Early-type Binaries: TU Mus and MP Cen | 
	 
	
		| Volume: | 
		318, Spectroscopically and Spatially Resolving the Components of Close Binary Stars | 
	 
	
		| Page: | 
		215 | 
	 
	
		| Authors: | 
		Terrell, D.; Munari, U.; Zwitter, T.; Nelson, R.H.; Wolf, G.W. | 
	 
	
	
		| Abstract: | 
		We have begun a project to gather modern data on early-type overcontact and near-contact binaries, systems about which very little is known. The overcontact systems consist of O, B and A-type stars that are in physical contact with one another, similar to their late-type cousins the W UMa systems. We are obtaining high resolution (R ≈ 50000) spectra to analyze simultaneously with high precision photometry. Our goal is to have the most accurate parameters possible for a variety of early-type systems that are in various stages of their evolution for comparison to 3D structural models that are in development. Here we present results on TU Muscae, an O-type overcontact system and MP Centauri, a B-type semidetached system. We have derived accurate masses and radii for the systems and show that TU Mus has had a constant orbital period over the thirty years of observations that we analyzed. This result for TU Mus may imply that the mass transfer seen in the W UMa systems does not occur in the early-type overcontact systems. | 
	 
	
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