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A&A Supplement series, Vol. 123, May II 1997, 1-4

Received June 3; accepted September 13, 1996

Four colour photometry of late-type binary systems

I. First tex2html_wrap_inline834 light curves of ZZ Ursae Majorisgiftex2html_wrap_inline836gif

R. Clementtex2html_wrap860 - M. Garcíatex2html_wrap862 - V. Reglerotex2html_wrap864 - J.V. Clausentex2html_wrap866 - A. Bravotex2html_wrap868 - J. Susotex2html_wrap870 - J. Fabregattex2html_wrap872 - J.M. Torrejóntex2html_wrap874 - P. Reigtex2html_wrap876 - A. Marcotex2html_wrap878

Send offprint request: R. Clement

tex2html_wrap880  Departamento de Astronomía y Astrofísica, Universidad de Valencia, Dr. Moliner 50, E-46100 Burjassot, Valencia, Spain
tex2html_wrap882  Departamento de Física Aplicada, E.U.I.T. Industrial, Universidad Politécnica de Madrid, Ronda de Valencia 3, E-28012 Madrid, Spain
tex2html_wrap884  The Niels Bohr Institute for Astronomy, Physics and Geophysics, Astronomical Observatory, Brorfeldevej 23, DK-4340, Töllöse, Denmark


This paper presents first complete uvby light curves of the late-type detached eclipsing binary ZZ UMa (tex2html_wrap_inline840, tex2html_wrap_inline842). This binary system has been observed during eight campaigns at the Calar Alto Observatory (Almeria, Spain)and at the Sierra Nevada Observatory (Granada, Spain). 294 points distributed over the binary period and covering both eclipses are given. The comparison stars used to calculate the differential light curves (SAO 15242 and SAO 15251) were confirmed as being good reference stars with constant flux. These observations are part of a 6 year uvby and tex2html_wrap_inline846 monitoring program of low mass eclipsing binaries whose main objective is to provide accurate absolute astrophysical parameters for late-type main sequence stars. Details about the standardisation process and accuracy of the photometry are also given. The internal accuracy of the standard photometry measured as the mean RMS of the differences between standard and observed values for the standard stars observed along the program is only a few millimagnitudes. Detailed analysis of ZZ UMa, based on these light curves, will be published separately.

keywords: stars: binaries: eclipsing -- stars: late-type -- stars: individual: ZZ UMa -- stars: fundamental parameters

Copyright by the European Southern Observatory (ESO)