EDP Sciences
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Volume 487, Number 3, September I 2008
Page(s) 1081 - 1093
Section Stellar structure and evolution
DOI http://dx.doi.org/10.1051/0004-6361:200809670
Published online 24 June 2008

A&A 487, 1081-1093 (2008)
DOI: 10.1051/0004-6361:200809670

Four-colour photometry of eclipsing binaries. XLI.

uvby light curves for AD Bootis, HW Canis Majoris, SW Canis Majoris, VZ Hydrae, and WZ Ophiuchi
J. V. Clausen1, L. P. R. Vaz2, J. M. García3, A. Giménez4, 5, B. E. Helt1, E. H. Olsen1, and J. Andersen1, 6

1  Niels Bohr Institute, Copenhagen University, Juliane Maries Vej 30, 2100 Copenhagen Ø, Denmark
    e-mail: jvc@astro.ku.dk
2  Depto. de Física, ICEx, UFMG, CP 702 - 30.123-970 - Belo Horizonte, MG, Brazil
3  Departamento de Física, E.U.I.T. Industriales, UPM, Ronda de Valencia 3, 28012 Madrid, Spain
4  Laboratorio de Astrofísica Espacial y Física Fundamental, INTA, Apartado 50727, 28080 Madrid, Spain
5  Research and Scientific Support Department, ESA, ESTEC, 2200 AG Nordwijk, The Netherlands
6  Nordic Optical Telescope Scientific Association, Apartado 474, 38 700 Santa Cruz de La Palma, Spain

Received 28 February 2008 / Accepted 25 May 2008

Context. Accurate mass, radius, and abundance determinations from binaries provide important information on stellar evolution, fundamental to central fields in modern astrophysics and cosmology.
Aims. Within the long-term Copenhagen Binary Project, we aim to obtain high-quality light curves and standard photometry for double-lined detached eclipsing binaries with late A, F, and G type main-sequence components, needed for the determination of accurate absolute dimensions and abundances, and for detailed comparisons with results from recent stellar evolutionary models.
Methods. Between March 1985 and July 2007, we carried out photometric observations of AD Boo, HW CMa, SW CMa, V636 Cen, VZ Hya, and WZ Oph at the Strömgren Automatic Telescope at ESO, La Silla.
Results. We obtained complete ${\it uvby}$ light curves, ephemerides, and standard ${\it uvby}\beta$ indices for all six systems. For V636 Cen and HW CMa, we present the first modern light curves, whereas for AD Boo, SW CMa, VZ Hya, and WZ Oph, they are both more accurate and more complete than earlier data. Due to a high orbital eccentricity (e = 0.50), combined with a low orbital inclination ( $i = 84\fdg7$), only one eclipse, close to periastron, occurs for HW CMa. For the two other eccentric systems, V636 Cen (e = 0.134) and SW CMa (e = 0.316), apsidal motion has been detected with periods of $5270 \pm 335$ and $14\,900 \pm 3600$ years, respectively.

Key words: stars: evolution -- stars: fundamental parameters -- stars: binaries: close -- stars: binaries: eclipsing -- techniques: photometric

© ESO 2008