Evaluating Gaia performances on eclipsing binaries

IV. Orbits and stellar parameters for SV Cam, BS Dra and HP Dra

¹ Physics and Astronomy Department, University of Calgary, Calgary T2N 1N4, Canada e-mail: marrese@strw.leidenuniv.nl
² Osservatorio Astronomico di Padova, Sede di Asiago, 36012 Asiago (VI), Italy
³ Dipartimento di Astronomia dell'Università di Padova, Osservatorio Astrofisico, 36012 Asiago (VI), Italy
⁴ University of Ljubljana, Department of Physics, Jadranska 19, 1000 Ljubljana, Slovenia
⁵ BASF-AG, Scientific Computing (GVC/S-B009), 67056 Ludwigshafen, Germany
⁶ Department of Astronomy, University of Florida, Gainesville, FL, USA
⁷ Centre for Astronomy, Nicholaus Copernicus University, ul. Gagarina 11, 87-100 Torun, Poland

Received: 20 January 2005
Accepted: 26 May 2005

Abstract

This is the fourth in a series of papers that aim both to provide reasonable orbits for a number of eclipsing binaries and to evaluate the expected performance of Gaia of these objects and the accuracy that is achievable in the determination of such fundamental stellar parameters as mass and radius. In this paper, we attempt to derive the orbits and physical parameters for three eclipsing binaries in the mid-F to mid-G spectral range. As for previous papers, only the H_P, V_T, B_T photometry from the Hipparcos/Tycho mission and ground-based radial velocities from spectroscopy in the region 8480-8740 Å are used in the analyses. These data sets simulate the photometric and spectroscopic data that are expected to be obtained by Gaia, the approved ESA Cornerstone mission to be launched in 2011. The systems targeted in this paper are SV Cam, BS Dra and HP Dra. SV Cam and BS Dra have been studied previously, allowing comparisons of the derived parameters with those from full scale and devoted ground-based investigations. HP Dra has no published orbital solution. SV Cam has a β Lyrae type light curve and the others have Algol-like light curves. SV Cam has the complication of light curve anomalies, usually attributed to spots; BS Dra has non-solar metallicity, and HP Dra appears to have a small eccentricity and a sizeable time derivative in the argument of the periastron. Thus all three provide interesting and different test cases.