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Paper: Multiplicity Survey of Bright Stars in the Nearby OB Associations
Volume: 510, Stars: From Collapse to Collapse
Page: 325
Authors: Balega, Yu. Yu.; Dyachenko, V. V.; Maksimov, A. F.; Malogolovets, E. V.; Rastegaev, D. A.
Abstract: We present the results of a speckle interferometric multiplicity survey of bright members of six OB associations: Per OB2, Per OB3 (α Per), CasTau, Lac OB1, Cep OB2, and Cep OB6.The observations were made with the diffraction spatial resolution of the 6-m BTA telescope in the period 2007–2016. To prepare the sample of 390 targets, we made use of the association member lists formed by de Zeeuw et al. (1999) using the Hipparcos astrometric data. The majority of the targets in the list (65%) fall into the category of intermediate-mass stars A5–B4, while only 77 objects (20%) refer to massive O and early B stars. We discovered 35 new binaries among the association members. Using the results of speckle interferometry, together with the literature and catalogue data on wide astrometric binaries, spectroscopic pairs and occultation binaries, we found that the average fraction of binaries and multiples (frequency of multiple systems) in the six associations is 0.28. The average number of components per star is 0.34. We established that the mass ratio distribution of the studied systems follows f(q)∝ qγ with γ = –0.7±0.2, in the range q = 0.3–1.0. Below q = 0.3, the difficulties of the detection of low-mass companions lead to uncertainties in the distribution.
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