A photometric study of the contact binaries V523 Cas and TY UMa |
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Authors: | T A Lister R M McDermid R W Hilditch |
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Institution: | School of Physics and Astronomy, University of St. Andrews, St. Andrews, Fife KY16 9SS;Department of Physics, University of Durham, South Road, Durham DH1 3LE |
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Abstract: | Broad-band V and I photometry of the short-period W UMa-type contact binaries V523 Cas and TY UMa are reported. From the light curves, the system parameters have been determined and evidence is presented for extensive spot activity in both systems, with V523 Cas being the more active system. A compilation of all the available photoelectric and CCD-based timings of eclipse minima is made; the O–C diagrams show evidence for an increasing period in the case of V523 Cas and a decreasing period in TY UMa. In addition we derive a more accurate astrometric position for V523 Cas from our CCD images. |
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Keywords: | stars: activity stars: atmospheres binaries: eclipsing stars: fundamental parameters stars: late-type |
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