The pre-main-sequence eclipsing binary ASAS J052821+0338.5^*

¹ School of Physics & Astronomy, University of St Andrews, North Haugh, St Andrews KY16 9SS, Scotland e-mail: Eric.Stempels@st-andrews.ac.uk
² Physics and Astronomy Department, Vanderbilt University, Nashville, TN 37235, USA
³ Astronomy Department, New Mexico State University, Las Cruces, NM 88003, USA
⁴ Nordic Optical Telescope, Apartado 474, 38700 Santa Cruz de La Palma, Spain
⁵ Department of Physics and Astronomy, Århus University, Denmark

Received: 31 August 2007
Accepted: 30 January 2008

Abstract

Aims. In this paper we present the first results of a detailed spectroscopic and photometric analysis of the eclipsing binary ASAS J052821+0338.5.

Methods. With the FIES spectrograph at the Nordic Optical Telescope, we obtained a series of high-resolution spectra () covering the entire orbit of the system. In addition we obtained simultaneous broadband photometry from three small aperture telescopes. From these spectroscopic and photometric data we have derived the system's orbital parameters and determined the fundamental stellar parameters of the two components.

Results. Our results indicate that ASAS J052821+0338.5 is a K1/K3 pre-main-sequence eclipsing binary, with component masses of and and a period of 3.87 days, located at a distance of pc. The kinematics, physical location, and the evolutionary status of the two stars suggest that ASAS J052821+0338.5 is a member of the ~11 Myr old Orion OB1a subassociation. The systems also exhibits smooth ~ out-of-eclipse variations that are similar to those found in RS CVn binaries. Furthermore, the parameters we derived are consistent with the Myr isochrones of the popular Baraffe stellar evolutionary models.