A&A 539, A129 (2012) Astronomy DOI: 10.1051/0004-6361/201117386 & c ESO 2012 Astrophysics A fresh insight into the evolutionary status and third body hypothesis of the eclipsing binaries AD Andromedae, AL Camelopardalis, and V338 Herculis A. Liakos1,P.Niarchos1, and E. Budding2,3 1 University of Athens, Department of Astrophysics, Astronomy and Mechanics, 157 84 Zografos, Athens, Greece e-mail: [alliakos;pniarcho]@phys.uoa.gr 2 Carter Observatory & School of Chemical and Physical Sciences, Victoria University, Wellington, New Zealand 3 Department of Physics and Astronomy, University of Canterbury, Christchurch, New Zealand e-mail:
[email protected] Received 1 June 2011 / Accepted 11 January 2012 ABSTRACT Aims. We aim to derive the absolute parameters of the components of AD And, AL Cam, and V338 Her, interpret their orbital period changes and discuss their evolutionary status. Methods. New and complete multi-filter light curves of the eclipsing binaries AD And, AL Cam, and V338 Her were obtained and analysed with modern methods. Using all reliably observed times of minimum light, we examined orbital period irregularities using the least squares method. In addition, we acquired new spectroscopic observations during the secondary eclipses for AL Cam and V338 Her. Results. For AL Cam and V338 Her, we derive reliable spectral types for their primary stars. Statistical checks of orbital period analysis for all systems are very reassuring in the cases of V338 Her and AD And, although less so for AL Cam. The LIght-Time Effect (LITE) results are checked by inclusion of a third light option in the photometric analyses.