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arXiv · 0711.4916

Variable stars in the field of open cluster NGC 6939

G. Maciejewski·Ts. Georgiev·A. Niedzielski
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Abstract

The results of CCD photometric survey performed with the 90/180 cm Schmidt-Cassegrain Telescope of the Nicolaus Copernicus University Astronomical Observatory in Piwnice (Poland) and the 70/172 cm Schmidt Telescope of the National Astronomical Observatory (NAO) at Rozhen (Bulgaria) of the field of 1 Gyr old open cluster NGC 6939 are presented. Twenty two variable stars were detected, four of them previously known. Four eclipsing systems (3 detached and 1 contact binary) were found to be members of the cluster. Analysis of the brightness of the contact binary V20 strongly supports the distance to the cluster of 1.74 +/- 0.20 kpc. The small population of contact binaries in NGC 6939 confirms also the relatively young age of the cluster.

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G. Maciejewski, Ts. Georgiev, A. Niedzielski. 2007-11-30. Variable stars in the field of open cluster NGC 6939. https://arxiv.org/abs/0711.4916

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