A&A 532, A148 (2011) Astronomy DOI: 10.1051/0004-6361/201116742 & c ESO 2011 Astrophysics AlargeHα line forming region for the massive interacting binaries β Lyrae and υ Sagitarii D. Bonneau1, O. Chesneau1, D. Mourard1, Ph. Bério1,J.M.Clausse1, O. Delaa1,A.Marcotto1, K. Perraut2, A. Roussel1,A.Spang1,Ph.Stee1, I. Tallon-Bosc3, H. McAlister4,5, T. ten Brummelaar5, J. Sturmann5, L. Sturmann5, N. Turner5, C. Farrington5, and P. J. Goldfinger5 1 Lab. H. Fizeau, Univ. Nice Sophia Antipolis, CNRS UMR 6525, Obs. de la Côte d’Azur, Av. Copernic, 06130 Grasse, France e-mail:
[email protected] 2 UJF-Grenoble 1/CNRS-INSU, Inst. de Planétologie et d’Astrophysique de Grenoble (IPAG) UMR 5274, Grenoble 38041, France 3 Univ. Lyon 1, Observatoire de Lyon, 9 avenue Charles André, Saint-Genis Laval 69230, France 4 Georgia State University, PO Box 3969, Atlanta GA 30302-3969, USA 5 CHARA Array, Mount Wilson Observatory, 91023 Mount Wilson CA, USA Received 17 February 2011 / Accepted 1 July 2011 ABSTRACT Aims. This study aims at constraining the properties of two interacting binary systems by measuring their continuum-forming region in the visible and the forming regions of some emission lines, in particular Hα, using optical interferometry. Methods. We have obtained visible medium (R ∼ 1000) spectral resolution interferometric observations of β Lyr and of υ Sgr using the VEGA instrument of the CHARA array. For both systems, visible continuum (520/640 nm) visibilities were estimated and differential interferometry data were obtained in the Hα emission line at several epochs of their orbital period.