Evaluating GAIA performances on eclipsing binaries

II. Orbits and stellar parameters for V781 Tau, UV Leo and GK Dra

¹ University of Ljubljana, Department of Physics, Jadranska 19, 1000 Ljubljana, Slovenia
² Osservatorio Astronomico di Padova, Sede di Asiago, 36012 Asiago (VI), Italy
³ CISAS, Centro Interdipartimentale Studi ed Attività Spaziali dell'Università di Padova, Italy
⁴ Dipartimento di Astronomia dell'Università di Padova, Osservatorio Astrofisico, 36012 Asiago (VI), Italy
⁵ Physics and Astronomy Department, University of Calgary, Calgary T2N 1N4, Canada
⁶ Centre for Astronomy, Nicholaus Copernicus University, ul. Gagarina 11, 87-100 Torun, Poland

Corresponding author: T. Zwitter, tomaz.zwitter@fmf.uni-lj.si

Received: 7 February 2003
Accepted: 18 March 2003

Abstract

The orbits and physical parameters of three close, double-lined G0 eclipsing binaries have been derived combining  photometry from the Hipparcos/Tycho mission with 8480–8740 Å ground-based spectroscopy. The setup is mimicking the photometric and spectroscopic observations that should be obtained by GAIA. The binaries considered here are all of G0 spectral type, but each with its own complications: V781 Tau is an overcontact system with components of unequal temperature, UV Leo shows occasional surface spots and GK Dra contains a δ Scuti variable. Such peculiarities will be common among binaries to be discovered by GAIA. We find that the values of masses, radii and temperatures for such stars can be derived with a 1–2% accuracy using the adopted GAIA-like observing mode.